Sulfoxides as Stereochemical Controllers in Intermolecular Heck Reactions

The study of a variety of substituted sulfoxides as chiral auxiliaries in intermolecular Heck reactions of sulfinyldihydrofurans and sulfinylcyclopentenes with different iodoarenes is reported. In the presence of [Pd(OAc)2]/Ag2CO3 and a bidentate phosphine ligand, synthetically useful yields and asymmetric inductions were obtained. By far the best diastereoselectivities were obtained by the use of the palladium-coordinating O-(N,N-dimethylamino)phenylsulfinyl group. By final removal of the chiral auxiliary, these sulfoxide-stereocontrolled asymmetric Heck processes were applied to the enantioselective synthesis of 1-aryl-substituted and 1,3-diaryl-substituted dihydrofurans and cyclopentenes.