Conjugate Addition Reactions Mediated by Samarium(II) Iodide

Samarium(II) iodide in conjunction with a catalytic low-valent transition metal species has been employed to promote the conjugate addition reaction of primary and secondary alkyl halides onto alpha,beta-unsaturated esters and amides. The method has been determined to be quite general and hence has been extended to the cyclization reactions of alkyl halides onto alpha,beta-unsaturated lactones, lactams, and nitriles. The cyclization reactions described herein provide a very general approach to the synthesis of functionalized carbocycles from simple acyclic precursors with excellent diastereoselectivity and under very mild reaction conditions.