Photochemically Promoted Aza-Diels–Alder-Type Reaction: High Catalytic Activity of the Cr(III)/Bipyridine Complex Enhanced by Visible Light Irradiation

• DOI: 10.1021/acs.joc.7b00838
• Publication Date: 2017-06-27T12:38:59Z
• Authors: Noriyoshi Arai; Takeshi Ohkuma
• Keywords: Bipyridine; 2,2'-Bipyridine; Molar ratio; Diels–Alder reaction

Aza-Diels-Alder-type cycloaddition reactions between a range of N-arylimines and functionalized alkenes were effectively catalyzed by the Cr(III)/bipyridine complex under irradiation blue light, to give corresponding 1,2,3,4-tetrahydroquinoline derivatives in high yields with excellent diastereoselectivity. Typically, reaction benzylideneaniline 1-vinyl-2-pyrrolidinone proceeded smoothly substrate-to-catalyst molar ratio (S/C) 1000 completed within 4 h at room temperature (20-25 °C), affording product 97% yield.