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

Photoinduced hydrogen abstraction from aliphatic cyclic hydrocarbons (C-5 t o C-7, C-12, as well as adamantane) by triplet aromatic ketones in the pres ence 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 b eta slows down the addition to mononitriles, but with alpha,alpha -dinitril es electronic activation allows efficient alkylation also of beta,beta -dis ubstituted substrates). A tandem alkylation-cyclization process has been ob tained with (1-methylpent-4-enylidene)malononitrile.