Dabbling with air-stable organoaluminum species

Highly stereoselective 1,2-additions of AlMe or its air-stable analog DABCO(AlMe to aldehydes are realized in the presence of a Ni(acac) -derived catalyst using phosphoramidite ligands giving -alcohols in up to 95 % ee. Very high turnover number (TON) (>1500) and turnover frequency (TOF) (>350 h ) values can be realized in these reactions. The substrate range, trials of various (DABCO) (AlR reagents ( = 0.1; = 1.2; R = Me, Et, Bu ), ligands, and molecular modeling studies are used to propose a working model for the catalytic cycle and the origin of the stereoselectivity. The phosphoramidite ligand is proposed to bind the nickel in an η manner via the -donor and one of the C=C aryl bonds of the CHAr amine group. Preliminary studies indicate that DABCO(AlMe can also be used as a methyl source in Pd-catalyzed cross-coupling reactions of ArX (X = Br, I) species.