Cyclopropyl Building Blocks for Organic Synthesis, Part 100. Advanced Syntheses of Cyclopropylideneacetates–Versatile Multifunctional Building Blocks for Organic Synthesis
作者:Michael Limbach、Suryakanta Dalai、Armin de Meijere
DOI:10.1002/adsc.200404025
日期:2004.6
A well reproducible and inexpensive preparation of the cyclopropylideneacetates 2–4 has been developed. The key intermediate 2-(1′-mesyloxycyclopropyl)acetic acid (8), produced either from methyl phenylacetate (1) or 3,3-dimethoxypropionate (5-Me) and 3,3-diethoxypropionate (5-Et) in a sequence of Kulinkovich reductive cyclopropanation, mesylation and oxidative cleavage or cleavage and oxidation, respectively
已开发出一种可重复性良好且价格低廉的环亚丙基乙酸酯 2-4 制备方法。关键中间体 2-(1'-甲磺氧基环丙基)乙酸 (8),由苯乙酸甲酯 (1) 或 3,3-二甲氧基丙酸 (5-Me) 和 3,3-二乙氧基丙酸 (5-Et) 按顺序生产Kulinkovich 的还原环丙烷化、甲磺酰化和氧化裂解或裂解和氧化分别转化为苄酯 11b,或通过原位形成的酰氯氯化(溴化)。α-氯- 12a 和 α-溴酯 12b 通过用三乙胺处理脱氢甲磺酸化,得到 2-氯-2-亚环丙基乙酸甲酯 (3-Me) 和 2-溴类似物 4-Me,总产率为 68% (从 1 (5-Me, 5-Et) 开始,分别为 65%、68%) 和 52% (49%、51%)。