Intramolecular aminocyanation of alkenes by N-CN bond cleavage.

A metal-free, Lewis acid promoted intramolecular aminocyanation of alkenes was developed. B(C6F5)3 activates N-sulfonyl cyanamides, thus leading to a formal cleavage of the N-CN bonds in conjunction with vicinal addition of sulfonamide and nitrile groups across an alkene. This method enables atom-economical access to indolines and tetrahydroquinolines in excellent yields, and provides a complementary strategy for regioselective alkene difunctionalizations with sulfonamide and nitrile groups. Labeling experiments with (13)C suggest a fully intramolecular cyclization pattern due to the lack of label scrambling in double crossover experiments. Catalysis with Lewis acid is realized and the reaction can be conducted under air.

Palladium catalyzed intramolecular acylcyanation of alkenes using α-iminonitriles.

Reported here is a palladium catalyzed intramolecular acylcyanation of alkenes using α-iminonitriles. Through this method, highly functionalized indanones are synthesized in moderate to high yields using Pd(PPh3)4, without need for any additional ligands, and a common Lewis acid (ZnCl2). Additionally, the reaction tolerates substitution at various positions on the aromatic ring including electron donating and electron withdrawing groups.

Palladium-catalyzed C-CN activation for intramolecular cyanoesterification of alkynes.

Conditions for the C-CN activation and intramolecular cyanoesterification of alkynes to provide butenolides in good to excellent yields are presented. Pd catalysts, high temperatures/short reaction times (microwave irradiation), and Lewis basic solvents minimized competitive decarbonylation. Less sterically encumbered, electron-rich alkynes underwent cyanoesterification with greater ease compared to sterically encumbered, electron-deficient alkynes. The results led to the hypothesis that migratory insertion of the alkyne, rather than C-CN activation, might be the product-determining step.