Reactions of aminoboron compounds with palladium and platinum complexes

Reactions of 3-NH2C6H4B(OH)(2) (1, APBA) with [MCl4](2-) (M = Pd, Pt) give the boronic acid-containing complexes, MCl2(APBA)(2) (M = Pd, 2; M = Pt, 3) . Addition of 1 to [PdCl2(COE)](2) (COE = eta(2)-C8H14) ultimately led to P dCl2(APBA)(2) (2). The pinacol derivative PdCl2(APBpin)(2) (5, pin = O2C2Me 4) was characterized by an X-ray diffraction study. Crystals of 5 were mono clinic, a = 13.836(5), b = 14.937(5), c = 11.287(5) Angstrom, beta = 99.042 (9)degrees, Z = 2, with space group P2(1)/c. Monoalkene complexes PtCl2(COE )(APBA) (8) and PtCl2(COE)(APBpin) (9) were generated from the addition of APBA and APBpin, respectively, to [PtCl2(COE)](2). Reactions of 2-NMe2CH2C6 H4B(OH)(2) (10) with palladium complex [PdCl2(COE)](2) proceed via selectiv e B-C bond cleavage to give the cyclopalladated dimer [PdCl(2-NMe2CH2C6H4)] (2) as the major amine-containing product. Likewise, reactions with borinic esters H2NCH2CH2OBR2 (R = Bu, 14; R = Ph, 15) give products derived from c leavage of the B-O bond. The unique palladium complex PdCl2[3-NC5H4B(OH)(2) ](2) (19) was prepared by addition of (3-NC5H4BEt2)(4) (18) to [PdCl2(COE)] (2) in wet methylene chloride, where adventitious water was used to convert the organoborane product into the corresponding boronic acid moiety.