Synthesis of ω-Hydroxy Ketones from ω-Benzyloxy Weinreb Amides by Using a Chemoselective Nucleophilic Addition/Birch Reduction Process

C Taillier, V Bellosta, C Meyer, J Cossy

Index: Taillier, Catherine; Bellosta, Veronique; Meyer, Christophe; Cossy, Janine Organic Letters, 2004 , vol. 6, # 13 p. 2145 - 2147

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Citation Number: 33

Abstract

Initially, the feasibility of the idea was investigated on the δ-benzyloxy Weinreb amide 1 using n-BuLi as a nucleophile. Addition of n-BuLi (5 equiv) in THF at −78 °C to compound 1 led to the lithiated tetrahedral intermediate of type II, 3 which was added to a solution of lithium in liquid ammonia [Li (excess), NH 3 (l)] at −78 °C. After 5 min, the reaction was quenched with solid ammonium chloride and the hydroxy ketone 2 was isolated in 78% yield (Table 1, entry 1). The ...