Stereoselective 1,4-Addition of Primary Alcohols to γ-Alkoxy-α,β-unsaturated Esters,Synthesis

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Stereoselective 1,4-Addition of Primary Alcohols to γ-Alkoxy-α,β-unsaturated Esters
Synthesis ( IF 2.6 ) Pub Date : 2020-09-22 , DOI: 10.1055/s-0040-1707274
Seiichi Nakamura , Saki Inatomi , Yuta Takayanagi , Kento Watanabe , Akinori Toita , Hiroyuki Yamakoshi ₁

Affiliation

Abstract

The scope and limitations of the diastereoselective 1,4-addition reaction of primary alcohols to γ-alkoxy-α,β-unsaturated esters were investigated. We found that a variety of sodium alkoxides, generated from the corresponding primary alcohols with NaH, underwent 1,4-addition reactions with (E)-enoates in CH₂Cl₂ at –23 °C to give β-alkoxy esters in modest yields with good to excellent syn-selectivity, whereas stereoselectivity was not observed with the use of glycerol derivatives as nucleophiles. Cyclic acetal protection was found to play a pivotal role for the reaction to proceed.

Publication History

Received: 03 July 2020

Accepted after revision: 07 August 2020

Publication Date:
22 September 2020 (online)

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany

中文翻译：

γ-烷氧基-α，β-不饱和酯对伯醇的立体选择性1,4-加成

摘要

研究了伯醇对γ-烷氧基-α，β-不饱和酯的非对映选择性1,4-加成反应的范围和局限性。我们发现，由相应的伯醇与NaH生成的各种烷醇钠，在–23°C下与CH ₂ Cl ₂中的（E）-烯酸酯进行1,4-加成反应，以中等收率得到β-烷氧基酯具有良好至优异的顺选择性，而使用甘油衍生物作为亲核试剂未观察到立体选择性。发现环缩醛保护对于反应的进行起关键作用。