Organocatalytic asymmetric cascade cyclization reaction of o-hydroxy cinnamaldehydes with diphenylphosphine oxide

A highly stereoselective asymmetric cascade cyclization reaction between o-hydroxycinnamaldehydes and diphenylphosphine oxide has been achieved with 84%–99% ee and 7:1-20:1 dr under the catalysis of l-diarylprolinol silyl ether. This reaction provides a facile access to highly enantioenriched 4-diphenylphosphinyl chroman-2-ols. It also represents a novel organocatalytic asymmetric phospha-Michael addition of α,β-unsaturated aldehydes with pentavalent P-nucleophiles.