Synthesis of chiral 1,5-disubstituted pyrrolidinones via electrophile-induced cyclization of 2-(3-butenyl)oxazolines derived from (1R,2S)- and (1S,2R)-norephedrine
作者:Iván Kanizsai、Zsolt Szakonyi、Reijo Sillanpää、Matthias D’hooghe、Norbert De Kimpe、Ferenc Fülöp
DOI:10.1016/j.tetasy.2006.11.006
日期:2006.11
Starting from (1R,2S)- and (1S,2R)-norephedrine, enantiomers of the corresponding 2-(3-butenyl)oxazolines were prepared in a two-step process. The cyclization of the intermediate alkenylamides with phenylselenyl bromide afforded cyclic imidates instead of the expected pyrrolidinones. The electrophile-induced cyclizations of 2-alkenyloxazolines with bromine or iodine produced diastereomeric mixtures of