Barbero Asunción, Castreño Pilar, Fernández Gloria, Pulido Francisco J
Departamento de Química Orgánica, Facultad de Ciencias, C/Dr Mergelina s/n, 47011 Valladolid, Spain.
J Org Chem. 2005 Dec 23;70(26):10747-52. doi: 10.1021/jo051868g.
[reaction: see text] Epoxyallylsilanes bearing the bulky tert-butyldiphenylsilyl group undergo an uncommon tandem rearrangement-cyclization process upon treatment with Lewis acids. Two pathways for the carbonyl ene reaction are observed: one leading to allylsilane-cyclohexanols when the epoxyallylsilane (28-31) is nonsubstituted, 2-, or 4-monosubstituted and other leading to vinylsilane-cyclohexanols when the epoxyallylsilane (24-27) is 2,4-disubstituted or trisubstituted. An explanation for the observed regio- and stereoselectivity is advanced and a reliable mechanism proposed.
[反应：见正文] 带有庞大叔丁基二苯基硅基的环氧烯丙基硅烷在路易斯酸处理下会经历一种不常见的串联重排-环化过程。观察到羰基烯反应的两条途径：当环氧烯丙基硅烷（28 - 31）未被取代、2 - 单取代或4 - 单取代时，一条途径导致烯丙基硅烷 - 环己醇；当环氧烯丙基硅烷（24 - 27）是2,4 - 二取代或三取代时，另一条途径导致乙烯基硅烷 - 环己醇。对观察到的区域和立体选择性提出了解释并提出了可靠的机理。
