Stereoselective Synthesis of Substituted ( Z )- N -Allyl Sulfonamides via a Palladium-Catalyzed Three-Component Tandem Reaction.

This paper reports the efficient synthesis of substituted ( Z )- N -allyl sulfonamides via a palladium-catalyzed three-component tandem reaction of N -buta-2,3-dienyl sulfonamides with iodides and sulfonyl hydrazide or sulfinic acid sodium salt as nucleophiles. Pd(PPh 3 ) 4 (2.5 mol %), K 2 CO 3 , and THF were used as the optimal catalyst, base, and solvent, respectively. The substituted ( Z )- N -allyl sulfonamides were obtained in a 30-83% overall yield. Mechanistic investigations revealed that the formation of the single ( Z )-isomer was controlled by the formation of a six-membered palladacycle intermediate.