A concise and enantioselective approach to cyclobutanones by tandem asymmetric epoxidation and enantiospecific ring expansion of cyclopropylidene alcohols. An enantiocontrolled synthesis of (+)- and (-)-.alpha.-cuparenones
作者:Hideo Nemoto、Hiroki Ishibashi、Masatoshi Nagamochi、Keiichiro Fukumoto
DOI:10.1021/jo00032a021
日期:1992.3
A tandem Katsuki-Sharpless asymmetric epoxidation and enantiospecific ring expansion of 2-alkyl(or 2-aryl)-2-cyclopropylideneethanols (1a-i) afforded chiral 1-alkyl(or 1-aryl)-1-(hydroxymethyl)cyclobutanones (3a-i) in high yields and high enantiomeric excess. These compounds are potentially valuable synthons for the enantioselective creation of the quaternary carbons. Hence, this enabled us to accomplish a concise and enantioselective total synthesis of both (+)- and (-)-alpha-cuparenones (11).