A Novel photosystem for harvesting visible light to drive photoinduced electron transfer (PET) reductions: β-activation of α, β-unsaturated ketones for radical cyclizations

Abstract

Now reductions induced by sunlight are also possible. The photosystem here, which absorbs visible light and transfers electrons from an electron donor D to an electron acceptor A and then to a substrate, is composed of D = Ph₃P and A = dicyanoanthracene. Enones 1 were chosed as substrates. After reduction to the radical anion they cyclize to form 2. This conversion is a variant of a cyclization mediated by tin hydride but without toxic side products. R = CN, CO₂Et; n = 1, 2.