156955-26-9Relevant articles and documents
Synthesis, reactions, and rearrangement of X(PR′3)2M[C(=PR)X] (M = Pt, Pd; X = Cl, Br; R′ = Et, Ph; R = 2,4,6-tri-tert-butylphenyl): Mechanism of the transition metal promoted conversion of X2C=PR to R-C≡P
Jun, Hyoung,Young Jr., Victor G.,Angelici, Robert J.
, p. 2444 - 2453 (2008/10/08)
Oxidative addition reactions of X2C=PR (X = Cl, Br; R = 2,4,6-tri-tert-butylphenyl) with M(PEt3)4 (M = Pt, Pd) or (C2H4)Pt(PPh3)2 initially yield the cis isomer of square planar (X)-(PR′3)2M[C(=PR)X] (II); these complexes (IIa-IId), where PR′3 is PEt3, rearrange rapidly in the presence of free PEt3 to give the trans isomers (Ia-Id). In contrast, the cis isomers (IIe and IIf), where PR′3 is PPh3 and M is Pt, react further to give R-C≡P and cis-X2Pt(PPh3)2. In polar solvents (CH2Cl2 and CHCl3), all the addition products (I and II) convert to R-C≡P and cis- or trans-X2M(PR′3)2 via the surprising phosphabicyclo intermediate (X)(PR′3)2Pt-(X-PBC) (III and IV); the structure of IIIa was established crystallographically. In the presence of H2O, (X)(PEt3)2Pt[C(=PR)X] (Ia and Ib where X = Cl, Br) give the oxophosphabicyclo complex (X)(PEt3)2Pt[(H)O=PBC] (Va and Vb) which was characterized by X-ray diffraction. A mechanism for the conversion of (X)(PR′3)2M[C(=PR)X] to R-C≡P and X2M-(PR′3)2 is proposed.
