QuestionOrganic / E2 stereochemistry
The major product formed in the following reaction is:
- (a) Alkene: Ph/Me cis, Me/H cis
- (b) Terminal alkene (3-phenylbut-1-ene)
- (c) Alcohol (substitution product)
- (d) Alkene: Ph/H cis, Me/Me cis
Answer: (d)
NaOEt/EtOH on a 2° tosylate → anti-periplanar E2. Rotating C3–OTs anti to C2–H places Me and Me cis, Ph cis to H → (E)-2-phenylbut-2-ene drawn in (d) → (d). Remember: E2 is stereospecific.