(2,5-diphenylphospholyl)-2-methylpyridine and 2-methyl-5R-phenyloxazoline PdCl2 complexes:: Syntheses, X-ray crystal structures and use in the Miyaura and Heck coupling reactions

Reaction of the (2,5-diphenylphospholyl)-2-methylpyridine ligand 1 with [PdCl2 (COD)] affords the expected chelate complex 2, which was structurally characterized. Complex 2 catalyses the cross coupling reaction between pinacolborane and iodoaromatics to afford the corresponding arylboronic esters with TON up to 100 x 10(3) and with TON up to 90 x 10(2) in the case of bromoaromatics. The (2,5-diphenylphospholyl)-2-methyl-5R-phenyloxazoline ligand 3 was synthesized by reaction of the 2,5-diphenylphospholide anion with 2-chloromethyl-5R-phenyloxazoline in good yields. The [PdCl2(3)] complex 4 catalyses the asymmetric cross-coupling reaction between iodobenzene and 2,3-dihydrofuranne with low enantiomeric excess under classical conditions. X-ray crystal structures of ligand 3 and complex 4 were recorded. (C) 2004 Academie des sciences. Published by Elsevier SAS. All rights reserved.