A facile method for the rapid and selective deprotection of methoxymethyl (MOM) ethers
摘要:
We describe a rapid and efficient method for selective deprotection of methoxymethyl (MOM) ethers using ZnBt(2) and n-PrSH, which completely removed MOM from diverse MOM ethers of primary, secondary. and tertiary alcohols or phenol derivatives The deprotection takes less than ten minutes with both high yield and selectivity in the presence of other protecting groups In addition, the rapid deprotection of MOM ethers of tertiary hydroxyls in high yield with no epimerization allows MOM to be a suitable protecting group for tertiary alcohols (C) 2010 Elsevier Ltd All rights reserved
A large number of fluorination methods have been developed, but the construction of a tertiary C–F bond remains challenging. Herein, we describe an efficient dehydroxylative fluorination of tertiaryalcohols with Selectfluor via the activation of a hydroxyl group by a Ph2PCH2CH2PPh2/ICH2CH2I system. Although the reagents appear to be not compatible (Selectfluor with the phosphine and I– generated in
combination of “TiCl2(cat)” and Zn (cat=catecholate) facilitates the homolytic cleavage of “non-activated” alcohol C−O bonds. All aliphatic primary, secondary and tertiary alcohols serve as good substrates. This method was applied to radical conjugate addition reactions successfully, and mechanistic studies indicate that alkyl chlorides are not intermediates. The active species is a 1 : 2 complex of alkoxide
We describe a rapid and efficient method for selective deprotection of methoxymethyl (MOM) ethers using ZnBt(2) and n-PrSH, which completely removed MOM from diverse MOM ethers of primary, secondary. and tertiary alcohols or phenol derivatives The deprotection takes less than ten minutes with both high yield and selectivity in the presence of other protecting groups In addition, the rapid deprotection of MOM ethers of tertiary hydroxyls in high yield with no epimerization allows MOM to be a suitable protecting group for tertiary alcohols (C) 2010 Elsevier Ltd All rights reserved