Visible Light-Induced Copper-Catalyzed Alkylation/exo-Cyclization of 1,7-Dienes with Sulfonium Salts to Access Sulfur-Containing Polycyclic Compounds

Abstract

A direct visible-light-promoted radical-triggered tandem cyclization of 1,7-diene systems with cyclic sulfonium salts by using copper(I)-based complexes as photoredox catalyst is developed. With this approach, a variety of sulfur-containing polycyclic derivatives are prepared through alkylation/6-exo-trig cyclization/5-exo-trig cyclization of 1,7-diene systems under mild conditions. In addition, the photoinduced copper-catalyzed ring-opening of cyclic sulfonium salts provides the alkyl radical intermediates, which prefers addition to the Ph-linked C-C double bond rather than the electron-deficient vinyl in 1,7-dienes. Moreover, oxidation of the desire sulfur-containing polycyclic products provides a strategy for the preparation of remote nitrogen-fused polycyclic substituted sulfoxide or sulfone-containing derivatives.