Organoaluminum Compounds as Catalysts for Monohydroboration of Carbodiimides

The effective catalytic activity of organoaluminum compounds for the monohydroboration of carbodiimides has been demonstrated. Two aluminum complexes, 2 and 3, were synthesized and characterized. The efficient catalytic performances of four aluminum hydride complexes L(1)AlH(2) (L(1)=HC(CMeNAr)(2), Ar=2,6‐Et(2)C(6)H(3); 1), L(2)AlH(2)(NMe(3)) (L(2)=o‐C(6)H(4)F(CH=N‐Ar), Ar=2,6‐Et(2)C(6)H(3); 2), L(3)AlH (L(3)=2,6‐bis(1‐methylethyl)‐N‐(2‐pyridinylmethylene)phenylamine; 3), and L(4)AlH(NMe(3)) (L(4)=o‐C(6)H(4)(N‐Dipp)(CH=N‐Dipp), Dipp=2,6‐iPr(2)C(6)H(3); 4), and an aluminum alkyl complex L(1)AlMe(2) (5) were used for the monohydroboration of carbodiimides investigated under solvent‐free and mild conditions. Compounds 1–3 and 5 can produce monohydroborated N‐borylformamidine, whereas 4 can afford the C‐borylformamidine product. A suggested mechanism of this reaction was explored, and the aluminum formamidinate compound 6 was characterized by single‐crystal X‐ray, also a stoichiometric reaction was investigated.