210562-06-4Relevant articles and documents
Formation of (diphenylphosphino)naphthalenes by double insertion of (alkynyl)diphenylphosphines into nickel(0)-benzyne complexes
Bennett, Martin A.,Cobley, Christopher J.,Rae, A. David,Wenger, Eric,Willis, Anthony C.
, p. 1522 - 1533 (2008/10/08)
(Alkynyl)diphenylphosphines Ph2PC≡CR (R = H, Me, Ph, PPh2) undergo double insertion into the nickel(0)-benzyne bond of the complexes [Ni{(1,2-η)-4,5-X2C6H2}(PEt 3)2] (X = H (1a), F (1b)) to give mixtures of nickel(O) complexes containing (diphenylphosphino)-naphthalenes, which in some cases are formed with high regioselectivity. Bromination of the mixtures of nickel(O) complexes obtained from Ph2PC≡CR (R = Me, Ph) and la or lb gives in high yield the chelate NiBr2 complexes [NiBr2{6,7-X2C10H2-1,4-Y 2-2,3-(PPh2)2}] (X = H, Y = Me (6a), Ph (11a); X = F, Y = Me (6b), Ph (11b)), from which the corresponding 1,4-disubstituted 2,3-naphthylenebis(diphenylphosphines) 12a, 13a, 12b, and 13b can be liberated by treatment with NaCN in DMSO at 60 °C or dimethylglyoxime/ammonia at room temperature. Derivatives in which only one of the phosphorus atoms is oxidized, 6,7-X2C10H2-1,4-Me2-2-PPh 2-3-P(O)PPh2 (X = H (15a), F (15b)), have also been prepared. The regioselectivity of the reactions of Ph2PC≡CH with 1b is poorer than that of Ph2PC≡CR (R = Me, Ph), and products with a 1,3-substitution pattern predominate. Reaction of Ph2PC≡CPPh2 (dppa) with la gives, after addition of bromine, a pair of isomers in which NiBr2 is attached to the phosphorus atoms at the 2,3- and 1,2-positions, respectively, of the tetrakis(tertiary phosphine) species C10H4-l,2,3,4-(PPh2)4 (19). The molecular structures of complexes lib and [NiBr2{C10H4-1,2)3-(PPh2) 3-4-{P(O)Ph2}-κ-P1,P2}] (18), and of a disordered 73:27 mixture of the bis(diphenylphosphine oxides) C10H4-1,4-(PPh2)2-2,3-{P(O)Ph 2}2 (20) and C10H4-1,2-(PPh2)2-3,4-{P(O)Ph 2}2 (21) obtained by partial oxidation of 19, have been determined by single-crystal X-ray diffraction. The regioselectivities of the insertions of Ph2PC≡CMe and Ph2PC≡CH into 1a and 1b are similar to those of MeC≡CCO2Me and HC≡CCO2Me, respectively, and factors that influence them are discussed.
