Organocatalytic asymmetric synthesis of functionalized 4 H -chromenes via a one-pot Domino Michael-Hemiacetalization and dehydration sequence

Article abstract of DOI:10.1055/s-0030-1260017

A one-pot thiourea-catalyzed enantioselective synthesis of polyfunctionalized 4H-chromenes via a domino Michael-hemiacetalization reaction and subsequent dehydration is reported. Starting from 2-nitrovinylphenols and -keto esters, the new protocol affords the 4H-chromenes bearing a variety of functional groups with good to excellent yields (76-95%) and enantioselectivities ranging from 30-99%ee. Both enantiomers are available at will depending on the ephedrine or pseudoephedrine-based thiourea catalyst used. Georg Thieme Verlag Stuttgart - New York.