Enantioselective 1,6-Conjugate Addition of Dialkyl alpha-Diazo Methylphosphonate to para-Quinone Methides

An asymmetric 1,6-conjugate addition reaction of dialkyl diazomethylphosphonates to para-quinone methides promoted by phase-transfer catalysis has been developed. A series of chiral diarylmethylated diazomethylphosphonates were accessed with up to 85% yields and 99% ee enantioselectivities. The resulting products were further transformed into bioactive compounds, namely, a chiral dihydrocinnoline phosphonate and a chiral alpha-aminophosphonate, bearing diarylmethine stereogenic centers.