Silicon-Oxygen Heterocycles from Thermal, Photochemical, and Transition-Metal-Catalyzed Decomposition of α-(Alkoxysilyl and Alkenyloxysilyl)-α-diazoacetates
作者:Gerhard Maas、Fred Krebs、Thorsten Werle、Volker Gettwert、Ruth Striegler
DOI:10.1002/(sici)1099-0690(199908)1999:8<1939::aid-ejoc1939>3.0.co;2-a
日期:1999.8
intramolecular C–H insertion of a carbene intermediate. Photochemical or catalytic decomposition of (allyloxysilyl)diazoacetates 3a–e results in intramolecular cyclopropanation which provides 3-oxa-2-silabicyclo[3.1.0]hexane systems 5a–e. In contrast, the thermal reaction of 3b–d gives rise to 2,5-dihydro-1,2-oxasiloles 4b–d, which are likely to be formed on a pyrazoline rather than a carbene route
(乙氧基)甲硅烷基-、(丙氧基)甲硅烷基-和(异丙基氧基)甲硅烷基取代的重氮乙酸酯 1a-c 的光解通过卡宾中间体的分子内 C-H 插入产生四氢-1,2-氧杂硅氧烷 2a-c。(烯丙氧基甲硅烷基)重氮乙酸酯 3a-e 的光化学或催化分解导致分子内环丙烷化,提供 3-oxa-2-硅杂双环 [3.1.0] 己烷系统 5a-e。相反,3b-d 的热反应产生 2,5-dihydro-1,2-oxasiloles 4b-d,它可能在吡唑啉而不是卡宾路线上形成。对于(3-丁烯氧基甲硅烷基)重氮乙酸酯 3f,所有分解模式都会生成 3-oxa-2-silabicyclo[4.1.0] 庚烷系统 7. 氟化物诱导的双环系统 5b-d 裂解提供反式-2-羟烷基-1 -环丙烷羧酸酯 9 非对映特异性。