404849-92-9Relevant academic research and scientific papers
Development of the first P-stereogenic PCP pincer ligands, their metallation by palladium and platinum, and preliminary catalysis
Williams, B. Scott,Dani, Paulo,Lutz, Martin,Spek, Anthony L.,Van Koten, Gerard
, p. 3519 - 3530 (2007/10/03)
The potentially tridentate P-stereogenic [P*CP*] ligands 1,3-{(bis[(tert-butyl)(phenyl)phosphino]methyl)-benzene and 1,3-{(bis[(tert-butyl)(phenyl) phosphino]methyl})1-2-bromobenzene have been synthesized as the protected phosphine-borane adducts. Deprotection with a secondary amine affords the free phosphine ligand which can be metallated by Pd and Pt with standard metal synthons. Two of the resultant [P*CP*] metal complexes have been characterized by X-ray crystallography. The complexes exhibit a C2 symmetric environment about the remaining binding site of the square-planar center, with t-Bu groups filling two quadrants of the open site. The Pd complexes can be converted by use of a Ag salt to the analogous aquo complex, which is catalytically active in the aldol condensation of methyl 2-isocyanoacetate and benzaldehyde. Preliminary results and comparisons with previously reported catalysts with more distal C-stereogenicity are presented.
