Photosensitized Hydride Transfer. Highly Regioselective 1,4-Photoreduction of NAD(P)+ Models under Visible Light with an Organometallic Rhodium(III) Porphyrin as Sensitizer

An organometallic acetyl-Rh complex of octaethylporphyrin catalyzes under the visible light the photoreduction of 1-benzylnicotinamide (BNA+) or l-benzyl-3-acetylpyridinium ion (BAP+) as NAD(P)+ model with tetraphenylborate as a reductant and an alcohol as a proton source to give the corresponding 1,4-dihydro derivative (BNAH or BAPH) as the sole reduction product and biphenyl as the oxidation product of B(C6H5)4.