For each pair, predict the stronger nucleophile in the

QUESTION:

For each pair, predict the stronger nucleophile in the \(\mathrm{S}_{\mathrm{N}} 2\) reaction (using an alcohol as the solvent). Explain your prediction.

(a)  \(left(\mathrm{CH}_{3} \mathrm{CH}_{2}\right)_{3} \mathrm{~N} \text { or }\left(\mathrm{CH}_{3} \mathrm{CH}_{2}\right)_{2} \mathrm{NH}\)

(b)  \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{O} \text { or }\left(\mathrm{CH}_{3}\right)_{2} \mathrm{~S}\)

(c)  \(\mathrm{NH}_{3} \text { or } \mathrm{PH}_{3}\)

(d)  \(\mathrm{CH}_{3} \mathrm{~S}^{-} \text {or } \mathrm{H}_{2} \mathrm{~S}\)

(e)  \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{N or}\left(\mathrm{CH}_{3}\right)_{2} \mathrm{O}\)

(f)  \(\mathrm{CH}_{3} \mathrm{COO}^{-} \text {or } \mathrm{CF}_{3} \mathrm{COO}^{-}\)

(g)  \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHO}^{-} \text {or } \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{O}^{-}\)

(h)  \(\mathrm{I}^{-} \text {or } \mathrm{Cl}^{-}\)

Problem-solving Hint

Steric hindrance (bulkiness) hinders nucleophilicity \(\left(\mathrm{S}_{\mathrm{N}} 2\right)\) more than it hinders basicity.

Equation Transcription:

Text Transcription:

S_N2

(CH_3CH_2)_3 N or (CH_3CH_2)_2NH

(CH_3)_2O or (CH_3)_2S

NH_3 or PH_3

CH_3S- or H_2S

(CH_3)_3N or (CH_3)_2O

CH_3COO- or CF_3COO-

(CH_3)_2CHO- or CH_3CH_2CH_2O-

I- or Cl-

(S_N2)