Asymmetric direct vinylogous aldolreactions of furan-2(5H)-one with aldehydes in the presence of a catalytic amount of novel squaramide–sulfonamide organocatalyst resulted in the corresponding addition products with high to excellent enantioselectivities. This is the first successful report illustrating an example of highly stereoselective reactions using a squaramide–sulfonamide organocatalyst.
diastereoselective vinylogous Mukaiyama aldol reaction is reported, between pyrrole/furan-based dienoxy silanes and aromatic aldehydes on salty water/methanol medium, at almost human body temperature, under ultrasonic irradiation. With pyrrole dienes the reaction is anti-selective, while that of furandienes is syn-selective. The dual role of water as both reaction medium and promoter is highlighted.