A facile and efficient anti-selective four-component direct aldol addition via chemoselective thioester enolate formation.

A facile and efficient four-component anti-selective direct aldol addition of thioester enolates has been developed that is fully compatible with enolizable aldehydes and able to be conducted using untreated reagent-grade CH2Cl2 open to the air. The thioester enolates are generated in situ via an acylation/conjugate addition sequence using commercially available PhSLi and acryloyl chloride, thus avoiding prior enolate formation while maintaining complete chemoselectivity. The organosulfur products are convertible into various polyketide-based structures.