Enantioselective organocatalyzed functionalization of benzothiophene and thiophenecarbaldehyde derivatives

Herein we report a study on the enantioselective organocatalyzed cross-aldol reaction of 1-benzothiophene and thiophenecarbaldehydes with different ketones. The reactions were conducted at 0 °C or room temperature to afford the corresponding adducts in high yields and good to excellent ee using different organocatalysts. Interestingly, using (S)-pyrrolidine tetrazole and acetoxyacetone an inversion of the aldol regiochemistry was observed.