Journal of the American Chemical Society, Vol.141, No.41, 16362-16373, 2019
Cyclohexyl-Fused, Spirobiindane-Derived, Phosphine-Catalyzed Synthesis of Tricyclic gamma-Lactams and Kinetic Resolution of gamma-Substituted Allenoates
A C-2-symmetric chiral phosphine catalyst, NUSIOC-Phos, which can be easily derived from cyclohexyl-fused spirobiindane, was introduced. A highly enantioselective domino process involving pyrrolidine-2,3-diones and gamma-substituted allenoates catalyzed by NUSIOC-Phos has been disclosed. Diastereospecific tricyclic gamma-lactams containing five contiguous stereogenic centers were obtained in high yields and with nearly perfect enantioselectivities. A kinetic resolution process of racemic gamma-substituted allenoates was developed for the generation of optically enriched chiral allenoates.