The influence of lithium complexing agents on the regioselectivity of reductions of substituted 2-cyclohexenones by LiAlH 4 and LiBH 4

A Loupy, J Seyden-Penne

Index: Loupy, Andre; Seyden-Penne, Jacqueline Tetrahedron, 1980 , vol. 36, p. 1937 - 1942

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Citation Number: 22

Abstract

A reversal of regioselectivity of LiAlH4 or LiBH4 reduction of 2-cyclohexenone induced by addition of [2.1. 1]-cryptand to the reaction medium is accompanied by a rate decrease. In the absence of the cryptand, carbonyl attack predominates (C1: C3= 86: 14 with LiAlH4 in THF). In the presence of the cryptand, double bond attack is favoured (C1: C3= 14: 86). This effect is larger with LiAlH4 than with LiBH4. This trend is general in the case of five ...