Enantioselective, Lewis Base-Catalyzed Sulfenocyclization of Polyenes.

Zhonglin Tao, Kevin A Robb, Kuo Zhao, Scott E Denmark

Journal of the American Chemical Society 2018 Mar 14

filter terms:

A sulfenium-ion-initiated, catalytic, enantioselective polyene cyclization is described. Homogeranylarenes and ortho-geranylphenols undergo polycyclization in good yield, diastereoselectivity, and enantioselectivity. The stereodetermining step is the generation of an enantiomerically enriched thiiranium ion from a terminal alkene and a sulfenylating agent in the presence of a chiral Lewis basic catalyst. The use of hexafluoroisopropyl alcohol as the solvent is crucial to obtain good yields. The thioether moiety resulting from the reaction can be subsequently transformed into diverse oxygen and carbon functionality postcyclization. The utility of this method is demonstrated by the enantioselective syntheses of (+)-ferruginol and (+)-hinokiol.

Citation

Zhonglin Tao, Kevin A Robb, Kuo Zhao, Scott E Denmark. Enantioselective, Lewis Base-Catalyzed Sulfenocyclization of Polyenes. Journal of the American Chemical Society. 2018 Mar 14;140(10):3569-3573