Highly Enantioselective Organocatalytic Michael-Aldol Domino Reactions

Significance

l-Proline derivative 1 catalyzed domino reactions of thiol 2 with α,β-unsaturated aldehydes 3 are reported. A Michael-aldol domino reaction takes place in the presence of benzoic acid as additive providing tetrahydrothiophene carbaldehydes 4 in good yields and with excellent enantio- and diastereoselectivities. Under basic conditions (NaHCO₃), the Michael addition is followed by enolization of the Michael adduct, yielding (tetrahydrothiophen-2-yl)phenyl methanones 5 with moderate yields and enantioselectivities.