Intro to Organic Chemistry
Intro to Organic Chemistry CHEM 2300
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Date Created: 10/28/15
Naming Alkanes bV the IUPAC Method 1 Unbranched Alkanes Pre XCw 1 5 2 3 7 4 9 10 CH3CH2CH2CH3 CH3CH25CH3 CH3H2 CH2CH2H2 CH3 II Branched Alkanes AlkylGroups 4 main chain CH3 alkyl substituent Name alkar yl eX CH3 CH2CH3 III Naming Branched Alkanes l N Locate longest continuous carbon chain Name that alkane parent name of molecule CH3 H CH2 CH3 CH2 CH3 eX CH3 CH CH2 CH3 CH2 CH3 CH3 CH2 CH3 CH CH CH2 CH3 CH2 CH2 CH3 eX CH3 CH2 CH3 CH CH CH2 CH3 I CH2 CH2 CH3 Special cas 7 If more than one equally longest chain select one with the greater number of substituents ex ICH3 H3 CH3 CH CH CH CH3 CH3 CH H CH CH3 CH3 CH2 CH3 CH3 CH2 CH3 Number carbons of parent chain so that rst substituent gets the lowest possible number CHZCH3 CH3 CH3 CH2 CH CH2 CH CH3 ex ICHZCH3 ICH3 CH3 CH2 CH CH2 CH CH3 Special case 7 Two lSt substituents equidistant from each end of parent chain a number so that 2quotd substituent gets lowest possible number ex ICH3 ICH3 CH3 I ICH3 CH3 CH3 CH3 CH CH CH2 CH CH3 CH3 CH CH CH2 CH CH3 b If there is no 2quotd substituent give the substituent that comes rst alphabetically the lower number eX CH3 CH2 CH3 CH3 CH2 CH CH2 CH CH2 CH3 3 Designate position of substituents based on numbering scheme developed in step 2 ex CH2CH3 CH3 CH3 CH2 CH CH2 CH CH3 Common case 7 If 2 or more identical groups are attached to parent chain use pre xes di 2 tri 3 tetra 4 penta 5 hexa 6 etc to group them together ex H3 H3 CH3 CH CH CH2 CH3 Common case 7 If attached to same carbon give them both the same number ex CH3 CH3 c CH2 CH2 CH3 CH3 4 Putting it all together a Name is all one word No spaces b List substituents rst in alphabetical order ignoring pre xes di tri etc followed by parent name Numbers 7 separated by commas Numbers and names 7 separated by hyphens FL Practice Naming 39 quot J Alkanes Hs CH3 CHCH2 CH3 CH3 CH2 CH2 H3 CH3 CH2 CH CH CH2 CH3 CH3 CH2 CH2 H3 CH3 CH CH CH2 CH3 A Alkenes and Alkynes quotUCJ N E 4 Naming Alkenes and Alkynes Alkanes Pre XC Alkenes Alkynes Dienes CH2 CH2 propene HCECH i propyne Substituted Alkenes and Alkynes Locate longest continuous carbon chain containing both carbons of multiple bond gt name of the parent compound Number carbons of parent chain from the end closer to the multiple bond Indicate the position of the multiple bond by using the lower numbered carbon atom of that bond for gt 3 C List substituents position of double bond parent name as one word with proper punctuation CH2CHCHzCH3 CH3CH2 quotD CHZCHZCH3 CH2 C1 CH3 CHCH 3 CH3 CH3 9H3 CH3 l3 CECCH3 Special Case If multiple bond is equidistant from both ends of parent chain begin numbering from the end nearest the rst substituent CH3 3CH CH3 not CH3 3CH CH3 CH3 CH3 C Dienes Locate longest chain containing both double bonds Indicate positions of both double bonds with lowest possible numbers CH23 CHCH CH3 CH3 CHc CHCH2 9H2 9H2 CH3 CH3 D Cycloalkenes Carbons in multiple bond are numbered 1 amp 2 in direction that gives substituents lowest possible numbers Cyclic Dienes Indicate positions of both double bonds using lowest numbers CO W IUPAC Common CH2 CH2 CH2CH CH3 CHECH as substituents CHCH2 CH2 Chapter 1 1 gt Structure Derivatives of ammonia in which 1 or more H s have been replaced by alkyl or aromatic groups NH3 CH31IH CH32N ltCgtgt CH3CH2NH CH2CH3 H Neutral N forms bonds 1 11 Classification 1quot 2quot or 3quot according to alkyl groups attached to N 112 Nomenclature 1 IUPAC COZH CO OH multiple bonds take precedence 0 6X NH2 2 Common Names alkyl groups amine 6X CH3CH2NH2 6X eX Draw ethylmethylamine NH2 NH4Jr alkyl groups ammonium Draw the dimethylammonium cation 113 Physical Progerties N H 1 E BP 9Q CH3 CHZCH3 CH3 CHZNHZ CH3 CHZOH Explain the following CH3CH2NH2 bp 17 C CH3 lI CH3 bp 29 0c CH3 2 Solubility Small low MW amines in water AsCT 1 16 Reactivity of Amines 1 of Amines RNH2 HOH The stronger the acid the its conjugate base gtiltgtilt NH3 pKa 93 CH3NH2 pKa 106 Trends in Basici gy 1 Inductive Effects H 9 GrpNH2 gt GrpNH3 Electrondonating groups IDLE NH3 CH3NH2 o Electronwithdrawing groups IDLE C6H5NH2 pC1C6H4NH2 2 Resonance Effects a Aromatic group NH2 NH2 pKa i pKa i Exglcmalion NH2 NH2 E i b Amines VS Amides 117 0 CH3CH2NH2 CH3CNH2 pKa gt Exglcmalion lol39 CH3CH2NH2 CH3C NH2 Basicity Summa Chapter 3 Rxn Summary ALKENES 1 Halogenation 2 Hydrogenation H H H2 czc gt C C N1 Pd or Ft 3 Hydration CC gt CC Markovm39kov39s Rule W 4 Addition of Acids CC gt CC Markovm39kov39s Rule W 5 HydroborationOxidation H 1 BH3 I I C C gt C C Anti Markovnikov H 2 H202 OH I I 5 OXidations a Potassium Permanganate KMnO4 RH EH 0 C gt C C b Ozonolysis CONJUGATED SYSTEMS H X H X HX CC CC gt C C CC C CC C 12addition 14addition X X X X X2 I I I I CC CC gt C C CC C CC C 12addition 14addition ALKYNES 1 Hydrogenation H H H2 I I CEC gt C C Ni Pd Pt I39i I39i H2 H H CEC gt Czc Stops at alkene stage Lindlar s catalyst CiSalkenes 2 Halogenation X X X2 X X2 CEC gt C gt 1 1 1110 X 2mol X X 3 Addition of Acids H X HX X HX I I I CEC gt 00 gt CC Markovmkovs 1 1 I I Rule mo H 2mol H X 4 Hydration H20H fl 1391 RH CEC T CH2 C via the enol CC Hg 5 Weak Acidity of Terminal Alkynes Na NH2 9 e CEC H gt CEC Na NH3 Chapter 9 functional group a aldehyde b ketone 91 Nomenclature A Aldehydes l IUPAC Select longest C chain that contains the carbonyl C alkanx al alker l al 0 n CH3C H CH3CH2CH2CHO Substituted Aldehydes a Number chain starting with the carbonyl C as 1 0 HCCH2HCH3 CH3 b Carbonyl has precedence over OH Named as aldehyde a1with OH as a substituent 0 HCCHZCHZOH 2 Common Names 3 HCH methanol I C H CH ethanol Skip naming cyclic aldehydes alkane carbaldehyde B Ketones l IUPAC Select longest C chain that contains the carbonyl C alkanX one 9 CH3CCH3 00 If C chain gt 3C indicate position of carbonyl number chain carbonyl C gets lowest possible o CH3CCH2CH2CH3 o CH3CHCH2CCH2CH3 13r o CH3CCH2CH20H Q Why don Z you need to indicate the position of the carbonyl in aldehydes Substituted cyclic ketones Number the ring starting with the carbonyl C as l in the direction that gives substituents lowest possible s Carbonyl is de ned to be 1 don t need to indicate this in the name 0 O CH3CH2 OCH3 r 2 Common Names a Name each group attached to carbonyl C kelone spaces 3 CH3CCH2CH3 0 CDQ CHZCH3 b Know I Order of precedence carbonyl gt alcohol gt alkene alkyne Unsaturated Aldehydes and Ketones Number so that the carbonyl gets the lowest number Ketones Break up the alkenone name like you did for alcohols and indicate the position of the double bond rst then the carbonyl alken one 0 CH3CHCHCCH3 Aldehydes You don t need to break up the name because the carbonyl is always terminal C 1 Only indicate the position of the double bond 0 HC CH2CH2CHZCH2 93 Synthesis of Aldehydes and Ketones l Oxidation of Alcohols Chapl 7 Jones 20 Alcohol gt Ketone PCC 10 Alcohol gt Aldehyde 2 Aromatic Acylation gt Ketones Chapl 4 3 Hydration of Alkynes gt Ketones Chapl 3 95 The Carbonyl Groug Bonding Geometgy R R CO CO R R Electronic Properties Resonance Reactions A Characteristic Rxn of carbonyl 96 General Rxn Mech If good Nu If weak Nu Reactivi gy of Aldehydes VS Ketones toward Nu gtXlt 1 0 O a a R R R H O 2 carbonyl polarization g alkyl groups Ketones VS Aldehydes Important Nucleophilic Addition Rxns 1 Addition of 2 Addition of 3 Addition of 4 Addition of 97 Addition of Alcohols O ROH y 2 RI H ex H CH3CH2CCH3 gt 1 mol CH30H CH3CH H gt excess Mechanism a aldehyde gt hemiacetal ketone b hemiacetal gt acetal a b Ketones and aldehydes w OH group 3 or 4 carbons away from carbonyl may exist as o HoCH2CH2CH2CH2 b H Common form of many carbohydrates ex glucose Addition of 00 CH CH3 Acetals as equilibrium reversibility important 8 H PR R39 H 2RQH R39 C H H20 OR add excess ROH add excess H20 H CH CH OH CH3CCH3 w 9CH3 H20 CH3CH2 g CH3 OCH3 Example of Use as Protecting Group 0 e H SN2 Want HCC BrCHZCH gt quot9 But HCEC BrCHZCH gt Solution n BrCHZCH 99 Addition of Grignard Reagents gt General Mech C RMgX gt gt The type of alcohol you make depends on the type of carbonyl you start with Formaldehyde gt 1 CH3MgBr gt 2 H20 H Other aldehydes gt O 1CH3MgBr CH3CH2 C H gt 2 H20 H Ketones gt 0 1 CH3MgBr gt CH CH C CH CH 3 2 2 3 2 H20 H 0 OH H 1 R39MgX R C H R H 2 H20 H I Show how the following could be made using a Grignard reagent and a carbonyl compound Chop o cm alkyl group gt Remainder gt OH a CH CH3 911 Addition of Amines gt Net Biological Importance Chapter 3 Chemistry of Vision retinal opsin gt rhodopsin protein light sensitive pigment 912 of Carbonyl gt Alcohols oxidation reduction PH CH3CCH3 gt CH3CHCH3 Reagents A EX Sources of Mech R HA1H3Li C gt 20 EX 0 gt 2 H20 0 1 LiA1H4 CH3CHCHC H gt 2 H20 Note B EX 0 n 1 LiA1H4 CH3CHCHC H gt 2 H20 21 Aldehydes and ketones both react similary with reducing agents a alcohols with oxidizing agents 913 Oxidation of Carbonyls Oxidize gain 0 lose H Aldehyde VS Ketone 0 H H C C l l 22 Reagents ex 0 Agzo CH2CHCH2CH gt Commercial Use to silver mirrors and glass Also during rxn Tollen s Silver Mirror test aldehyde AgZO ketone 23 914 Most aldehydes and ketones may exists as an equilibrium mixure of 2 forms Chapt 3 H H CH3CECH 2 0 O4 Predominant form Term 24 Requirement EX Which of the following exists only in the keto form Draw its enol form 0 0 II c H CCH33 CH3 0 EX Draw the keto form of OH 25 915 Acidity of ocH the Enolate Ion pKa CH3CH2CH3 CH3CCH3 CH3CH CH3CH20H Explanation Base 26 EX Draw the enolate anion for I CH3CH2CH EX Which molecule is more acidic R 0 II CH33CC CH3C 27 917 0m in which enoate anion is used as a C nucleophie amp attacks another carbonyl EX 0 0 gt Mech form anion Nu attack abstract H from H 20 28 EX Predict the product H OH 2 CH3CH2CH 918 Mixed Aldol Condensation can use two different carbonyl compounds Limitation ex Predict the product 3 CH3 OH CH3CH CH3 c CH gt CH3 29 95 Physical Progerties Types of Intermolecular Forces 1 2 3 For similarly sized molecules A BP of aldehydes and ketones Similar size O 0 CH3CH2CH2CH3 CH3CH2ampH CH3CCH3 CH3CH2CH2CHZOH BP Trend 30 B Solubility 0 CH3CH2CH2CH3 CH3CH26H CH3CCH3 CH3CH2CH2CH20H in H20 Like dissolves like 31 Cha ter 10 Rxn Summa Carbox lic Acids and Derivatives A Carboxylic Acids 1 Preparation of Carboxylate Anions Acidbase chemistry E E C OH NaOH gt C O39 Na H20 2 Preparation of Esters Fischer Esteri cation n H i C OH CH3OH gt C OCH3 H20 I H20 3 Preparation of Amides 9 9 0 C OH NH3 gt c O39NHX C NH2 H20 A 0 C2 H20 4 Preparation of Acyl Halides 0 E C OH SOC12 gt C Cl orPCl5 B Rxns of DerViatives Acid Chloride alcohol gt ester amine gt amide H20 gt carboxylic acid Acid Anhydride alcohol gt ester amine gt amide H20 gt carboxylic acid Ester amine gt amide H20 gt carboxylic acid Amide H20 gt carboxylic acid C Saponi cation of Esters Ester Na0H gt carboxylate ion 0 CH3CH2CH2CH2CH2COCH3 NaOH gt CH3CH2CH2CH2CH2CO39Na CH 30H D Reduction of Esters t0 alcohols CH3CH2C02CH3 LiAlH4 gt CH3CH2CH20H E Reaction of Esters with Grignards produces alcohols fl 1 CH3MgBr RH C OCHZCH3 gt C CH3 2 H20 I CH3 F Reduction of Amides t0 amines CH3CH2C0NH2 LiAlH4 gt CH3CH2CH2NH2 Chapter 7 Rxn SummarV Alcohols Phenols Thiols 1 Preparation of Alkoxides R OH Na gt R O39 Na H NaH NaOH is not strong enough of a base to form alkoxides but will form phenoxides from phenols 2 Dehydration If l H2804 or H CC gt CC H 20 I A OH Zaitsev s Rule The major alkene formed is the one with more alkyl substitutents on double bond to Alkvl Halides X Cl Br SOCl 3 2 R OH K R X also 2gt 1 R OH 194 P013 2 PBI 3 gt 4 Oxidation 1 Jones Reagent CrO3 H O l0 RCHZOH gt REOH carboxylic acid H 0 2 RCHR RER ketone 2 FCC Pyridinium Chlorochromate 0 1 RCHzOH gt RAH aldehyde OH 0 I 2 RCHR R CR ketoneD Chapter 9 functional group a aldehyde b ketone Nomenclature 91 A Aldehydes l IUPAC Select longest C chain that contains the carbonyl C alkar lt a1 alkerDK 31 n CH3C H CH3CH2CH2CHO Substituted Aldehydes a Number chain starting With the carbonyl C as I I HCCH23HCH3 CH3 b Carbonyl has precedence over OH Named as aldehyde al With OH as a substituent o n HCCHZCHZOH 2 Common Names I HCH methanol I C ethanol H CH3 wo Skip naming cyclic aldehydes alkane carbaldehyde B Ketones l IUPAC Select longest C chain that contains the carbonyl C alkanX one u CH3CCH3 00 If C chain gt 3C 7 indicate position of carbonyl number chain carbonyl C gets lowest possible n CH3CCH2CH2CH3 CH3CHCH2CCH2CH3 Br CH3CCH2CH20H Q Why don t you need to indicate the position of the carbonyl in aldehydes Substituted cyclic ketones Number the ring starting With the carbonyl C as l in the direction that gives substituents lowest possible s Carbonyl is de ned to be 1 don t need to indicate this in the name 0 O CH3CH2 OCH3 r 2 Common Names a Name each group attached to carbonyl C ketone spaces 0 CH3CCH2CH3 0 CCHZCH3 b Know 0 I II CH3 CH3 CCH3 Order of precedence carbonylgt alcohol gt alkene alkyne IT t J Aldehydes and Ketones Number so that the carbonyl gets the lowest number Ketones Break up the alkenone name like you did for alcohols indicate the position of the double bond rst then the carbonyl alken one o n CH3CHCHCCH3 Aldehydes n HCCHZCHZCHCH2 Synthesis of Aldehydes and Ketones 93 l Oxidation of Alcohols Chapt 7 Jones 2 Alcohol gt Ketone PCC l Alcohol gt Aldehyde 2 Aromatic Acylation gt Ketones Chapt 4 3 Hydration ofAlkynes gt Ketones Chapt 3 III The Carbonyl Groug 95 Bonding Geomet R R CO CO R R Electronic Properties Resonance IV Reactions A Characteristic erz of carbonyl A 96 General Rxn Mech If good Nu If weak Nu Reactivity of Aldehydes vs Ketones toward Nu C R R R H O 2 carbonyl polarization alkyl groups Ketones vs Aldehydes Important Nucleophilic Addition Rxns 1 Addition of 2 Addition of 3 Addition of 4 Addition of Addition of Alcohols 97 ex 0 H CH3CH2CCH3 1 mol CH3OH H CXCCSS CH3OH H CH3CH Mechanism a aldehyde gt hemiacetal cetorze b hemiacetal gt acetal 3 b Ketorzes and aldehydes w OH group 3 or 4 carbons away from carbonyl may exist as o HOCHZCHZCHZCHZHZH Common form of many carbohydrates ex glucose 2 Addition of O CH CH3 Acetals as equilibrium reversibility important 0 OR R H 2ROH R C H H20 add excess ROH add excess H20 0 H CH CH OH CH3CCH3 2 H 9CH3 H20 CH3CH2 ECH3 gt OCH3 H Example of Use as Protecting Group 0 quote u 8N2 Want HCEC BrCHZCHgt quot9 But HCEC BrCHZCH gt Solution II BrCHZCH 3 Addition of Grignard Reagents 99 gt General Mech CRMgX gt The type of alcohol you make depends on the type of carbonyl you start With Formaldehyde gt 1 CH3MgBr 2 H20 H Other aldehydes gt 0 1 CH3MgBr CH3CH2 C H gt 2 H20 H Ketones gt 0 1 CH3MgBr CH3CH2 C CH2CH3 2 H20 H n 1 R MgX R C H R C 2 H20 H 1I2 Show how the following could be made using a Grignard reagent and a carbonyl compound Chop o an alkyl group gt Remainder gt OH l a CHiCH3 b CH2 OH 4 Addition ofAmines911 gt 1 2 Meek I R C H NHZR l 3 Jr a em a CH CH3 Biological Importance Chapter 3 7 Chemistry of Vision retinal opsin gt rhodopsin protein light sensitive pigment B of Carbonyl gt Alcohols 912 oxidation reduction 3 PH CH3CCH3 CH3CHCH3 EX Sources of MeCh39 PI H A1H3Li C gt EX o 6 1NaBH4 2 H20 0 H 1L1A1H4 2 H CH3CHCHC7H 20 Note 2 H2 Pt o H EX CH3CHCHC7H Aldehydes and ketones both react similarly With reducing agents alcohols 7 With oxidizing agents C Oxidation of Carbonyls 913 Oxidize gain 0 lose H Aldehyde vs Ketone Reagents ex 0 l l Agzo CH2CHCH2CH Commercial Use to silver mirrors and glass Also during rxn Tollen s Silver Mirror test aldehyde AgZO ketone D Aldol Condensation 1 9 1 4 Most aldehydes and ketones may exists as an equilibrium mixure 0f2f0rms H20 H gt CH CECH Chapt 3 3 HgSO4 Predominant form Term Requirement EX Which of the following exists only in the keto form Draw its enol form 0 O I ll C C H CCH33 CH3 OH Draw the keto form of 6 2 Acidiy of ocH the Enolate Ion 915 pKa CH3CH2CH3 R CH3CCH3 S CH3CH CH3CHZOH Explanation Base gici EX Draw the enolate anion for H CH3CH2CH EX Which molecule is more acidic O H II CH33CC CH3C 3 917 nm in Which enolate anion is used as a C nucleophile amp attacks another carbonyl EX 0 0 CH3CH CH3CH gt Mech form anion Nu attack abstract H from H 20 EX Predict the product I OH39 2 CH3CH2CH 20 918 Mixed Aldol Condensation can use two different carbonyl compounds Limitation eX Predict the product 0 CH O n 3 H OH CH3CH CH3 I C H gt CH3 21 V Physical Properties 95 Types of Intermolecular Forces 1 2 3 For similarly sized small molecules A BP of aldehydes and ketones Similar size 0 0 CH3CH2CH2CH3 CH3CH2ampH CH3CCH3 CH3CH2CH20H BP Trend 22 B Solubili O 0 CH3CH2CH2CH3 CH3CH2ampH CH3CCH3 CH3CH2CH20H in H 20 Like dissolves like 23 Chapter 5 Stereoisomerism same molecular formula lsomers di erent arrangements of atoms structural constitutional di erent connectivity i of atoms i i di erent compounds Br CH 3 HCH3 conformatwnal HStrans 13T CH3CH2CH2 lmerconverted by NOT interconverted C c by C c same cmpd di cerent cmpds H H H CH3H CH3 CC g H CH3 CH3 CH3 H H H H CH3 H H CH3 C C CH3 H 51 amp 52 Chiral Molecules bisects molecule in such a way that everything on one side of plane is the exact re ection of every thing on other side 91 eX CH3CHCH3 C1 eX CH3c391HCH2CH3 3931 C1 Note CH3 ID CH2CH3 VS CH3 ID CH3 H H A compound with 1 NoC7 2 One Ci 3 gtoneC7 Chirali Worksheet For each of the following compounds a Does it contain a stereogenic center b Is it chiral or achiral c If it is chiral draw the 2 enantiomers l liodopropane 2 3methylpentane 3 3methylhexane 4 Gem 5 CH3 C1 6 CH3 CH3 C1 7 CC 53 Configuration and the RS Convention Cll Cl CH3CH2 H H CH2CH3 Con guration Convention Rules 1 4 groups on C are given priority order 1 highest priority 2 C is observed from side opposite lowest priority group 3 Draw curve from 1 to 2 to 3 Movement is clockwise gt counterclockwise gt Priori Rules 1 Rank by atomic of atom directly attached to C l3r Cl C H CHZI 2 If directly attached atoms are the same work outward until a difference is found CHZOH CHZCH3 C C CHZCH3 CH3 RS Worksheet eXl CH3 H CH3CH2 Cl 6X2 CH20CH3 CH3quot quot HO H CH2Br H2 CH20H3 eX4 NHZ CH3 Draw the S isomer of C1IHCH2CH3 U Multiple bonds If comparing like atoms triple bond gt double gt single CHCH2 CHCH2 CHO as c c CHZCH3 CEC H CHZOH But apply rules I and Zfirst EX Give a priority order to 7CHCH2 7CH2CH3 7CH2OH ioCHZCH3 54 EZ Convention for CisTrans Isomers CH3 CH CH CH 2 3 3 CC H H H 1 C C C Br EZ System Assign priority to 2 groups on each C of the double bond 2 If2 highest priority groups are a on same side of CC gt b on opposite sides of CC gt CH3 C1 gtCClt H Br CH3 CH CH 2 3 C HOCH2 CHCH CICH CH NH 2 2 2 C H Br 55 Measured by instrument 7 Ordinary light beam waves Vibrating in all directions to its path Polarizing lter Transmitted light all Vibrations parallel to one another Compound Find degrees that an optically active compound rotated the plane of polarized light Rotates light to right 7 Rotates light to left 7 Is there a relationship between R amp S and amp alanine glyceraldehyde lactic acid 0c85 0c87 0c333 Relationship between structure and optical activity 56 Properties of Enantiomers 0 Con guration 0 Physical properties Bp mp density Speci c Rotations eX lactic acid lactic acid 0 Chemical reactivity Rasparagine S asparagine What Will happen if you pass plane polarized light through a 5050 mixture of and lactic acid Will it rotate plane polarized light 3 things that are optically inactive 57 Fischer Projection Formulas A E B E D EX 1 H EX 2 Br BrCH3 H CH3 CH2CH3 CH2CH3 R or S 7 R or S Switch any 2 groups gt EX 3 H H Indentical Br CH3 CH3 Br or H2CH3 H2CH3 Enantiomers a By inspection b By PUS assignment EX 3 H CH2CH3 Indentical Br CH3 Br H or H2CH3 H3 Enantiomers Fisher Pro39ection NoNo s 1 Not allowed to pick them up out of the plane of paper and turn them over Br Br HCH3 7 Lgt CH3 H C1 C1 R S 2 Not allowed to rotate 90 C in the plane of the paper Br H H l CH3 7 c1Br Cl CH3 R s 3 Are allowed to rotate 1800 in the plane of the paper Br Cl HCH3 gt CH3 H Cl Br R R 4 Switch any two groups gt opposite con guration Assign con guration at each stereocenter CH3 Br H H C1 58 Compounds With more than one Stereogenic Center Maximum of stereoisomers eX CH3 CH CH CH3 Br C1 1 2 Con guration of Enantiomers 7 Con guration of Diastereomers 7 Properties of Diastereomers 3 4 59 Meso compounds eX CH3 CH CH CH3 Br Br 510 Summary Stereochemical Definitions 1 A single isomer can be classi ed as chiral or achiral a Chiral 7 b Achiral i no stereocenter 7 ii one stereocenter 7 iii more than one stereocenter 7 N Pairs of stereoisomers can be classi ed by their interconversion a Can be interconverted by CC bond rotations 7 b Can t be interconverted by CC bond rotations i Enantiomers 7 ii Diastereomers 3 Meso Compound A Classify each of the following as chiral or achiral Hint look f0 stereocenters mirror planes of symmetry B B I r r H CH2CH3 CH3CH2 C1 CC Br B H CH3 H r Cl CH3 CH3 CH3 H OH H OH H OH HO H H OH H OH CH3 JH3 B Classify each of the following pairs of molecules as Enantiomers or Identical Rlactic acid Slactic acid Br Br CH3 OH HO CH3 Ill Ill c BEVCCH3 CH3 Br H H BrCH3 CH3CHZCH3 1 Cl CHZCH3 Br CH3 Cl Br H Classify each of the following pairs of molecules as Enantiomers Diastereomers or Identical CH3 CH3 CH3 CH3 HO H H OH Br H Br H H OH HO H Br H H Br CH3 CH3 CH3 CH3 3931 3931 2R3R CH3CHCHCH3 C1 C1 CH3 CH3 Br H H Br Br H H Br CH3 CH3 2R3 S CH3CHCH CH3 p 172 Chirali in a Biological World 1 39 I Ome Oxidation You don t need to memorize this eitheriit is just for those who were curious about how this proceeded I I CC C C C C I I AA 0 ym gt n H w 995 0 o 0 quotMn 99 o CC lt o O H 90H 0 0amp1 4 fMnf M OH A I O o 90 MnOH product or IC 0 90 OH I c c 6H Hfb H OH OH Major Classes of Organic Compound Example CH3CH2CH2CH3 CH3CHCHCH3 CH3CE CCHZCH3 CH3CH2CH2Br CH3CH2CH20H CH3CH2CHZSH CH3OCH2CH3 CH3CH2CH2CEN CH3CH2CH2NH2 0 II Carbonyl compounds C o CH3CH2l3H CH3CH2l3CH3 o CH3CH2l30H n CH3CH2COCH3 I CH3CH2CNH2 Class of Compound Functional Group Chapter 6 Organic Halogen Compounds Classi cation Common Name alkyl groups attached to C bearingX CH3CH21 CH3 CH3 BI39 CH3 Characteristic Rxns Alkenes amp alkynes i Aromatics i Alkyl Halides CX bond and Properties Alkanes C C amp CH bonds 39 a strong sigma b nonpolar rather unreaclz39ve Alkyl Halides CX Find 61 8 8 CH3CH2 Br QH39 gt Terms 1 CH3CH2 BIquot Br 62 Classification of Nucleophiles 1 Strength 2 Atom forming bond Nucleophile Type Nu RBr gt Product 0 OH39 CH3CH2Br CH3039 CH3CH2Br H20 CH33CBr HOCH3 CH33CBr N NH3 CH3CH2Br NH2CH3 S HS 39 CH3CH2Br CHgs 39 halogen I 39 CH3CH2Br C 62 CH CH3CH2Br EEN Requirement Note How would you prepare the following by a substitution rxn a gt b gt CH3 Alkyl Halides undergo both substitution and elimination Be aware If Nu is a strong base RX should be CH3CH2 Br OH39 gt CHa CH3 IC l OH39 gt CH3 Rxn Mechanisms Background information Stepwise description of how reactants are converted to products EX co2 on39 gt C03 H20 Mechanism C02 OHquot gt HC0339 HC0339 OH39 gt C03 H20 Steps will not all occur at same rate Slowest step Rate 0t 63 Nucleophilic Substitution Mechanisms 0139 64 E2 Mechanism 1 Bimolecular 2 Onestep rxn 3 Nu attacks 9H3 9H3 CH3CH239Cl139Br OH gt CH3CH2939OH Br39 H H 4 Occurs with Draw the product of CH3 NaI Br gt 39H SN2 CHZCH3 5 Rate of rxn as alkyl substitution on C Alkyl Halide Rate Explanation R R quotNC LG C LG H 10 R 30 When bulky groups interfere with a reaction due to their size For which compound will SNZ be fastest slowest CH3 CH3 65 l Mechanism 1 Unimolecular 2 Occurs in several steps Mechanismfor CH33CBr H20 gt 3 Occurs with CH3 H20 CH3CH2quot7 s 1 CH3CH2CH2 Br N Explanation lnterrnediate carbocation 9H3 CH3CH2 C 9 CH3CH2CH2 Adjacent alkyl groups donate electron density to the electron deficient center stabilizing it CH3 e CH3 EB CH3 CH2 CH3 5 Rate of rxn as alkyl substitution on C Alkyl Halide Rate Explanation Summ any R D S Stereochemis Alkyl Halide SNZ SNl 66 Factors Affecting Substitution Mechanism 1 Alkyl Halide 2 Solvent 3 Nucleophile 7 Trends in Nu strength ability to donate equot 21 OH VS H20 CH30 VS b Strength Nu OHquot or 8H NH3 or PH3 Brquot or Clquot 0 Strength Nu NHZ39 or Fquot H20 or HF SNl SNZ How Choice of Nu may Change Mechanism Nu Strength SH nl R OLRX Nu R 0t RX Moderate Strong Weak How to Predict Substitution Mechanism 1 Alkyl Halide Substitution Mechanism Worksheet Predict the mechanism SNl or SNZ of each of the following substitution reactions 1 CH33CBr CH3OH gt CH33COCH3 HBr 2 gt N31 3 CH3CHCH2CH3 CH30H gt CH3CHCH2CH3 HBI BI OCH3 G 4 CH3CHCH2CH3 SH gt CH3CHCH2CH3 B Br SH Substitution Compared in Alkyl Halides vs Aryl Halides EX How would you prepare the following molecule by a nucleophilic substitution reaction H2 Rxns in the Cell Biochemical Methylations Many biological processes take place by rxn pathways analogous to those carried out in the lab class Common groups in OCH3 naturally occurring compounds ITI39CH3 H SNZ In lab gt CH32CHOCH3 9 gt CH3CH2NH2CH3 base H CH3CH2NHCH3 In Cell aqueous environment need CH3I substitute HO OH sNz I o HO CH CHz NHzCH3 l Ht HO OH HO CH CH2 NHCH3 adrenaline Chapter 8 Common structural feature 81 Nomenclature of Ethers 1 Common Name name each group attached to O ether spaces alphabetical order CH3OCH2CH3 o CHZCHZCH3 If 2 groups the same alkyl ether CH3CHZOCH2CH3 2 IUPAC a 0R as a substituent is called an alkoxy group pre x C oxy OCH3 OCH2CH3 b To name the compound Locate the longest chain of C determines the parent name Remaining OR is named as a substituent CH3CH20CH2CH24CH3 CHZCH3 CH3CH2CH2cH0CH3 Draw structure for 4ethoxy l pentanol 82 Physical Properties of Ethers alcohol ether alkane CHECHZCHZCHZOH CHECHZOCHZCHE cchchchchH BP 0C 118 35 36 Solubility 79 75 003 in H20 gl OOmL 1 Boiling point 2 Solubilities 83 Ethers as Solvents Good solvent characteristics Common ether solvent EX CH3I Mg gt CH31 Mg gt Hazards of Ethers l CH3CHZOCH2CH3 02 84 example of General rxn Role of Etgo in Rxn Examples and Naming CH3I Br Reagent stabilizes the Grignara Reagent acts as a Lewis Reactivi of Grignard eX H20 gt Solvent consideration Can we prepare a Grignard reagent from the following HOCHZCHZCHZBr CH3 OCH2CH2CH2BI39 Not Useful Useful 113 Arrow Conventions in Chemistry ArrowPushing less common r Arrow starts Q the equot being moved and ends Q the point where equot end up H H COquot lt gt C b H 39 He quot9 NOT H CO H While arrowpushing be careful about charges movement of equot will normally result in the movement formation or disappearance of charges ArrowPushing Worksheet A Draw the structure that results when electrons move as indicated by the curved arrows Locate any formal charges that result 390 II p9 CH3 C C H CH3 mew e 3 C rgr CH3 CH3 B Add curved arrows to show how molecules on the left are converted to molecules on the right Locate any resulting formal charges If If 1 CH3 c CH3 H gt CH3 IC CH3 9H 9H H Q lt gt CH3 C g39j lt gt CH3 C NH NH2 9 3 CH3 C CH3 39H gt CH3 CH3 H 1 quot 39 I of Hydrnhnmtinn Oxidation 1 Hydroboration BH3 adds to alkene AntiMarkovnikov 3 CC BH3 gt 3 3 H Balky12 Oxidation Replacement of B by OH N You do not need to memorize this mechanism Just be able to predict the overall product as done in class a H202 ampNaOH react Hole OH H o oe H20 b HOO 39 reacts With Trialkylborane C C cc C C I I I I I I H Ba1ky12 H SB alky12 H 0 Ba1ky12 O H O oe H Or HOOe migration of alkyl and alkyl group to oxygen migration two more times 39c 39c alcohol product l l H 0 BOa1ky1 39C 39C I I 2 II IC e 39 H 0 3Oalky12 OH OH 2 3Oalkyl2 H O H OH OH39 Bonding and Hybridization Summag l sigma 6 bond overlap of hybrid orbitals pi 7 bond side by side overlap of p orbitals 2 single bond always 6 double bond l G l 7 triple bond l G 2 7 3 IC sp3 tetrahedral 109 5 2 39 o C sp trigonal planar 120 CE sp linear l 800 eX Describe the bonding in Stereochemical Classification Worksheet Answers A Classify as chiral 0r achiral Br Br I H CH2CH3 quotC CH3CH2 C1 cc Br H CH3 H Br Cl h 11quot quot0 Ch 11 one Stereoceme quot achiral no stereocenter stereocenter CH3 CH3 CH3 H OH H OH H OH HO H H OH H OH CH3 JH3 chiral achiral meso chiral B Enantiomers 0r Identical Rlactic acid Slactic acid Br Br enantiomers opposite con gurations CH3 OH HO CH3 H H C1 C1 enantiomers by visual inspection they quotIquot CquotIIIII BIEI CH3 C HBr have a C and are mirror images enantiomers by visual inspection H H they have a C and are mirror images B r CH3 CH3 CH 2CH3 R 13r S 1 CHZCH3 Br IquotWC IquotWC C131 Cl CH3 H Identical Assign con gurations and you 39ll 3 Br nd they are both S enantiomers assign con gurations and you 3911 nd one is R the other S C Enantiomers Diastereomers or Identical CH3 CH3 HO H H OH H OH HO H CH3 CH3 Enantiomers by inspection they are mirror images and not meso CH3 CH3 Diastereomers by inspection one con guration is the same the other diferent Identical meso compounds 3931 3931 2R3R CH3CHCHCH3 3931 3931 2R3 S CH3CHCH CH3 Diastereomers one con guration is the same and the other different