Diastereoselective formation of seven-membered oxacycles by ring-expansion of cyclopropanated galactal
摘要:
The cyclopropanation and ring-expansion of 4,6-O-di-(tert-butyl)silanediyl-D-galactal using catalytic amounts of TMSOTf and silated nucleophiles gave a range of substituted oxepanes. Good to excellent yields were obtained in addition to very high selectivities. (C) 2003 Elsevier Ltd. All rights reserved.
Diastereoselective formation of seven-membered oxacycles by ring-expansion of cyclopropanated galactal
摘要:
The cyclopropanation and ring-expansion of 4,6-O-di-(tert-butyl)silanediyl-D-galactal using catalytic amounts of TMSOTf and silated nucleophiles gave a range of substituted oxepanes. Good to excellent yields were obtained in addition to very high selectivities. (C) 2003 Elsevier Ltd. All rights reserved.
Mechanistic studies of rearrangements during the ring expansions of cyclopropanated carbohydrates
作者:Rhys Batchelor、Joanne E. Harvey、Paul Teesdale-Spittle、John O. Hoberg
DOI:10.1016/j.tetlet.2009.10.031
日期:2009.12
Deuterium-labeling studies have been performed on the ringexpansion of cyclopropanated carbohydrates. From these studies, mechanisms have been proposed for two unusual rearrangements. In addition, a selective deprotection of the 1,3-di-tert-butylsilyl ether protecting group at the secondary position versus the primary position has been observed. This is a high yielding transformation with the potential