Organocatalytic Site- and Stereoselective 1,6-Additions of N-Aryl-3-oxobutanamides to Propargylic Aza-p-Quinone Methides

A chiral phosphoric acid catalyzed site-selective 1,6-conjugate addition of N-aryl-3-oxobutanamides to in situ formed propargylic aza-p-quinone methides from propargylic alcohols has been established and this represents the first report on organocatalytic site- and stereoselective 1,6-conjugate addition of propargylic aza-para-quinone methides. Furthermore, the synthetic strategy enables the formation of diarylmethyl alkynes bearing vicinal quaternary and tertiary carbon stereocenters in high yields with high asymmetric induction.