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Sequencing Pericyclic Reactions: The Ester Dienolate [2,3]‐Wittig/Oxy‐Cope Rearrangement/Carbonyl Ene Reaction, a New Access to Substituted Carbocycles
Author(s) -
Hiersemann Martin
Publication year - 2001
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200102)2001:3<483::aid-ejoc483>3.0.co;2-f
Subject(s) - chemistry , ene reaction , pericyclic reaction , cyclopentane , wittig reaction , cope rearrangement , intramolecular force , rearrangement reaction , cascade reaction , stereochemistry , medicinal chemistry , organic chemistry , catalysis
The sequential ester dienolate [2,3]‐Wittig/oxy‐Cope rearrangement/carbonyl ene reaction has been investigated. Acyclic α,β‐unsaturated α‐allyloxy‐substituted esters 1a − j were transformed into cyclopentane‐ or cyclohexanecarboxylates 6a − f and 7a − 7d . This study presents a domino ester dienolate [2,3]‐Wittig/oxy‐Cope rearrangement or a domino oxy‐Cope rearrangement/carbonyl ene reaction, depending on the substrate structure. The thermal intramolecular type‐I carbonyl ene reaction as the terminating ring‐closing reaction proceeds with high simple diastereoselectivity, but low induced diastereoselectivity. The corresponding type‐II ene reaction afforded the cyclohexanecarboxylates 7a − d in high yield with complete simple and induced diastereoselectivity. Unfortunately, an attempted auxiliary‐controlled enantioselective sequence was inefficient.