Organocatalytic, Chemoselective Hydrophosphenylation/oxa-Michael Addition Cascade toward Diastereo- and Enantioenriched 1,3-Dihydroisobenzofuryl Phosphonates

An efficient method for the construction of chiral C–P bond via an enantioselective 1,2-hydrophosphenylation followed by an oxa-Michael addition cascade of ortho-formyl chalcones has been developed. This provides the diastereoenriched (cis)-1,3-dihydroisobenzofuryl phosphonates with excellent enantioselectivities (up to >99%). The origin of enantio- and diastereoselectivity is induced by using a chiral bifunctional organocatalyst. Further, functionalization to highly enantioselective 3-substituted phthalides has also been demonstrated.