Sulfoximine as E/Z Auxiliary: Stereoselective Synthesis of Trisubstituted Alkenes

Auxiliaries are crucial for achieving high selectivity in synthesizing complex molecules, particularly pharmaceuticals and natural products. However, their application has primarily been limited to specific selectivity, such as the stereoselectivity of asymmetric reactions and the regioselectivity of C–H functionalization. Our hypothesis was that expanding this concept to other reactions requiring high selectivity could enable the synthesis of otherwise challenging molecules. Here, we introduce a conceptually new auxiliary, aptly termed the “E/Z auxiliary,” for the stereoselective synthesis of trisubstituted alkenes. In this work, sulfoximines, mono-aza analogs of sulfones, proved effective for enabling two key reactions: the stereoselective condensation of alkyl sulfoximines with aryl aldehydes to afford alkenyl sulfoximines, and the subsequent Pd-catalyzed Suzuki-Miyaura cross-coupling for further arylation and alkenylation with retention of the original stereochemistry.