Hydrocarbon activation.: Synthesis of β-cycloalkyl (Di)nitriles through photosensitized conjugate radical addition

Photoinduced hydrogen abstraction from aliphatic cyclic hydrocarbons (C-5 to C-7, C-12, as well as adamantane) by triplet aromatic ketones in the presence of alpha,beta -unsaturated (di)nitriles offers a straightforward entry to the corresponding alkylated (di)nitriles via the alkyl radicals. Yields are moderate to good depending on the olefins structure (substitution in beta slows down the addition to mononitriles, but with alpha,alpha -dinitriles electronic activation allows efficient alkylation also of beta,beta -disubstituted substrates). A tandem alkylation-cyclization process has been obtained with (1-methylpent-4-enylidene)malononitrile.