Donor-Acceptor Binary Photocatalysis System Illustrated By The Intramolecular Cyclization Of A Cyclopropanone Acetal Tethered To Cyclohexen-2-One

Irradiation of 2-[3-(2-methoxy-1-phenyl-2-TBDMSO-cyclopropyl)-propyl]-2-cyclohexen-1-one (5) in the presence of Mg(CIO4)2 (1 mol equiv) and 9,10-dicyanoanthracene (DCA, 0.5 mol equiv) in acetonitrile formed methyl 5-oxo-1-phenyldecahydro-1-naphthaleneacetate (6) in 63% yield. When pyrene was adopted in place of DCA, the yield of 6 was 38%. The results indicate that the photocyclization of 5 induced by the SET can be catalyzed by both donor- and acceptor-type photocatalysts. Irradiation of a similar substrate, 4-(2-methoxy-1-phenyl-2-TBDMSO-cyclopropyl)butyl 2-naphthyl ketone (21), produced methyl 2-hydroxy-2-(2-naphthyl)-1-phenylcyclohexaneacetate (27) in 13% in the presense of p-dicyanobenzene (0 1 mol equiv) and 8% in its absence.