Addition of diphenylacetylene and methylvinylketone to aluminum complex of redox-active diimine ligand

Diphenylacetylene reacts with aluminum complex (dpp-bian)AlEt(Et2O) (1) (dpp-bian - 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) in the absence of any solvent at 110-130 degrees C under vacuum to give compound [dpp-bian(PhC=CPh)]AlEt (2). The reaction of methylvinylketone with complex 1 easily proceeds at ambient temperature in Et2O and results in the formation of compound [dpp-bian(CH2-CH=C(Me)-O)]AlEt (3). Both reactions proceed via addition of unsaturated organic substrate across Al-N-C bond sequence in complex 1. Complexes 2 and 3 have been characterized by IR and H-1 NMR spectroscopy. Molecular structures of 2 and 3 have been determined by single-crystal X-ray analysis. Complex 2 was found to be catalyst for the reaction between phenylacetylene and diphenylamine. A full conversion of the reagents was achieved with 5 mol% of complex 2 in benzene in 140 h at 110 degrees C resulting N-phenyl-2-(1-phenylvinyl)aniline (4a) as the major product (87%). (C) 2013 Elsevier B.V. All rights reserved.