NiCl2(dppe)-Catalyzed Geminal Dialkylation of Dithioacetals and Trimethylation of Ortho Thioesters
NiCl2(dppe)-catalyzed cross-coupling of cinnamaldehyde dithioacetals gave the corresponding geminal dimethylation products in excellent yields.Allylic ortho thioesters afforded regioselectively the corresponding trimethylation products.The reaction may occur via an 18-electron ?-allyl intermediate, which undergoes facile reductive elimination to afford the geminal dimethylation product.Benzylic dithioacetals having an ortho amino group gave 2-isopropylanilines exclusively.The reaction of benzylic dithioacetals with EtMgBr under the same conditions yielded geminal diethylation products.