Group transfer from silicon to carbon via tandem radical cyclizations of acylsilanes
作者:Yeun-Min Tsai、Kuo-Hsiang Tang、Weir-Torn Jiaang
DOI:10.1016/0040-4039(96)01773-x
日期:1996.10
Tandem radical cyclizations of acylsilanes with alkene or alkyne functionalities attached to silicon afforded cyclic silyl ethers which were oxidatively hydrolyzed to give diols or ketone alcohols.
[reaction: see text] Cation 9, generated by the reaction of diol 8 and BF(3).Et(2)O, SnCl(4), Sc(OTf)(3), FeCl(3), TiF(4), or CF(3)SO(3)H, leads to a hydride shift, providing cation 11, which corresponds to the initiation of backbone rearrangement. On the other hand, TiCl(4) selectively induces rearrangement to secondary cation 13 by ring expansion, which corresponds to the C-ring formation of sterol