Diastereoselective Epoxidation of Oxazolidine-Substituted Alkenes by Dimethyldioxirane and <i>m</i>-Chloroperbenzoic Acid: π-Facial Control through Hydrogen Bonding by the Urea Functionality
作者:Waldemar Adam、Simon B. Schambony
DOI:10.1021/ol006800w
日期:2001.1.1
[figure: see text] A high diastereoselectivity (up to > 98:2) is found for the DMD and m-CPBA epoxidations of chiraloxazolidine-substituted olefins with a urea group. The selectivity is explained in terms of hydrogenbonding between the remote NH group of the ureafunctionality and the epoxidizing reagent. Methylation of the NH group prohibits hydrogenbonding, and a reversed selectivity is observed
Diastereoselective and Regioselective Singlet-Oxygen Ene Reaction of Oxazolidine-Substituted Alkenes: Control through Hydrogen Bonding Mediated by the Urea Functionality of Chiral Auxiliaries
作者:Waldemar Adam、Karl Peters、Eva-Maria Peters、Simon B. Schambony