An Organocatalytic and Stereoselective Vinylogous Domino Process Towards Thiochromans.

A highly diastereoselective organocatalyzed domino Vinylogous sulfa-Michael-Aldol-Cyclocondensation (VMAC) reaction has been developed using alkylidene Meldrum's acid as dienes highlighting two vinylogous steps, an unprecedented sulfa-1,6-conjugate addition and a diastereoselective aldol reaction triggering a formal (4+2) cycloaddition. This work opens a new route to bio-relevant and original tricyclic thiochroman derivatives.