Visible-Light Photoredox-Catalyzed Cross-Dehydrogenative Coupling of Tetrahydroisoquinolines with 3-Fluorooxindoles

The 3-fluorooxindole and tetrahydroisoquinoline scaffolds are both important structures because of their associated biological and pharmaceutical activities. Herein, we report a highly diastereoselective synthesis of 3-fluorooxindoles fully substituted at the 3-position and containing a tetrahydroisoquinoline fragment, through the visible-light photoredox-catalyzed cross-dehydrogenative coupling of tetrahydroisoquinolines with 3-fluorooxindoles. The protocol featured a wide substrate scope: N-alkyl-, N-haloalkyl-, N-aryl-, N-allyl-, N-propargyl-, and NH 3-fluorooxinloles were all able to be used to form the desired coupling products in up to 92% yield and 99 : 1 anti/syn.