Diastereoselective addition of organometallic reagents to chiral iminium ions: Synthesis of (S)-(+)-cryptostyline I

Article abstract of DOI:10.1016/S0040-4039(00)94630-6

Iminium ion 2c participates in stereoselective nucleophilic addition reactions with Grignard reagents. Analysis of the products from reaction of 5-hexenylmagnesium bromide with iminium ion 2a suggests that these reactions proceed by a polar (two electron) mechanism. The utility of this chemistry is demonstrated in a stereo specific synthesis of (5)-(+)-cryptostylina I.