The crotyllithium compound 1 generated from (E)-2-(l-propen-l-yl)-1, 3-dithiane reacted with an aldehyde to give y-products in favor of the anti isomer. This regio-and diastereoselective reaction is applicable to syntheses of trans B, y-disubstituted y-lactones, including natural products of (A)-eldanolide and (&)-trans quercus lactone. The y (l, 2)-adducts obtained from the reaction of 1 and enah underwent alkoxy-Cope rearrangements on treatment with KH. ...
