Catalytic Enantioselective [3 + 2]-Cycloadditions of Diazoketone-Derived Aryl-Substituted Carbonyl Ylides
作者:David M. Hodgson、Rebecca Glen、Guy H. Grant、Alison J. Redgrave
DOI:10.1021/jo026307t
日期:2003.1.1
An evaluation of alpha-aryl-alpha-diazodiones in tandem carbonyl ylide formation-enantioselective [3 + 2]-cycloaddition reactions is described. Such substrates were designed to allow investigation of the electronic characteristics of the dipole upon asymmetric induction. Intramolecular cycloadditions (with a tethered alkene dipolarophile) were found to occur in good to quantitative yields, with a difference
In the presence of an acidic zwitterion bearing a highly stabilized carbanion, reactions of ,-dialkoxy carbonyl compounds with ketene silyl acetals (KSA) resulted in an unusual molecular transformation; substitution reaction with the KSA at the ketal moiety and simultaneous silylative acetalization of the ketone moiety.