双自由基促进的（N + 2 - 1）环扩展：一种合成大环酮的有效反应。

Diradical-promoted (N + 2 - 1) ring expansion: an efficient reaction for the synthesis of macrocyclic ketones.

作者信息

Rüedi Georg, Oberli Matthias A, Nagel Matthias, Hansen Hans-Jürgen

机构信息

Organisch-chemisches Institut der Universität, 8057 Zürich, Switzerland.

出版信息

Org Lett. 2004 Sep 2;6(18):3179-81. doi: 10.1021/ol048701e.

DOI:10.1021/ol048701e

PMID:15330617

Abstract

[reaction: see text] A diradical-promoted (n + 2 - 1) ring expansion reaction based on vinyl side chain insertion (+2C) and decarbonylation (-1C) has been developed. Flash vacuum pyrolysis (FVP) of medium- and large-ring 2-trimethylsilyloxy-2-vinyl-cycloalkanones at 500-600 degrees C affords the one-carbon ring-expanded cycloalkanones in good yields. Methyl groups on the vinyl moiety are transformed regiospecifically as corresponding alpha- and beta-substituents, respectively. 2-Ethynyl precursor analogues react in a manner similar to give alpha,beta-unsaturated cyclic ketones.

摘要

[反应：见正文] 已开发出一种基于乙烯基侧链插入（+2C）和脱羰（-1C）的双自由基促进的（n + 2 - 1）环扩展反应。在500 - 600℃下对中环和大环2 - 三甲基硅氧基 - 2 - 乙烯基 - 环烷酮进行快速真空热解（FVP），可高产率得到单碳环扩展的环烷酮。乙烯基部分上的甲基分别区域选择性地转化为相应的α - 和β - 取代基。2 - 乙炔基前体类似物以类似方式反应生成α，β - 不饱和环酮。