Reactions of Aldehydes and Ketones and Their Derivatives

The gold-catalyzed cyclization of 2-alkynylarylaldehyde cyclic acetals leads to indanone derivatives in good-to-excellent yields. It is possible to use photoimmobilized Ni clusters on a CdS photocatalyst to give imines by the dehydrogenation of amines under visible-light illumination. The process is suitable for primary and secondary amines. An intramolecular asymmetric reductive amination of aminoketones leading to chiral 1,4-diazepanes catalyzed by an imine reductase enzyme has been reported, which proceeds with high enantioselectivity. Aryl acetic acid esters and other active methylene compounds react with nitrosoarenes to give diastereoselective formation of ketonitrones using 2-t-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine catalyst at room temperature. Saturated aliphatic tricycles including an imine function have been cyclized by van Leusen imidazole synthesis using p-toluenesulfonyl-methyl isocyanide (TosMIC). N-(Tosylmethyl) formamide, a decomposition product of TosMIC, was further transformed into N-methyleneformamide under the basic conditions and acts as a catalyst to reduce reaction times and improve yields.