(a) Which of these molecules most readily undergoes an addition reaction?
(b) Which of these molecules is aromatic?
(c) Which of these molecules most readily undergoes a substitution reaction? [Section 24.3]
R=clockwise S=counterclockwise *for a tetrahedral 3D stereoformula -never two lines 180˚ -never all wedges -never all dashes Chiral=not superimposable Achiral=superimposable;if a molecule has a plane of symmetry and is superimposable *NOTE:be able to determine if the structure is R or S *NOTE:meso=more than one chirality center but achiral overall Optical activity=ability of a chiral substance to rotate plane-polarized light (ppl) -measured by a polarimeter l=levorotatory=counterclockwise rotation of ppl (-) d=dextrorotatory=clockwise rotation of ppl (+) =observed angle of rotation Speciﬁc rotation=physical property of a chiral compound Optically pure/homochiral/enantiomers=only one pure enantiomer in the sample racemic mixture=50% (-) enantiomer and 50% (+) enantiomer;optically impure *NOTE:The R-enantiomers can be (+) or (-) and then whatever R is,S will be the opposite sign. Cahn-Ingold-Prelog Rules for R,S Notation 1. Higher atomic mass takes precedence 2. Find point of ﬁrst difference 3. Work outward from point of attachment 4. Evaluate substituent atoms one-by-one 5. Multiply bonded is considered a replicated substituent Fischer Projections=horizontal lines are wedges and vertical lines are dashed wedges Carbohydrates=Cn(H20)n glycerol (glycerin) = OlderTerminology D=(+) L=(-) *NOTE:memorize aldoses on slide 4-14 Epimers=stereoisomers with more than one chiral center and the conﬁguration of o