Remote Stereocontrolled Construction of Vicinal Axially Chiral Tetrasubstituted Allenes and Heteroatom-Functionalized Quaternary Carbon Stereocenters.

The direct diastereo- and enantioselective 1,8-conjugate additions of thiazolones and azlactones, respectively, to para-quinone methides generated in situ from propargylic alcohols have been achieved in the presence of chiral phosphoric acids. The remote stereocontrolled activation protocol provides an efficient and facile approach for the construction of vicinal axially chiral tetrasubstituted allenes and heteroatom-functionalized quaternary carbon stereocenters, which expands the synthetic potential of chiral phosphoric acids.