137935-97-8Relevant academic research and scientific papers
Rigid P-chiral mono and diphosphines. Configurative stability and P-inversion barrier
Widhalm, Michael,Brecker, Lothar,Mereiter, Kurt
, p. 1355 - 1369 (2007/10/03)
A group of P-chiral monophosphine oxides and one diaryl diphosphine oxide based on the dibenzophosphole skeleton have been synthesized. Preparative enantioselective chromatography of 4-trimethylsilyl-5-phenyl-5H-dibenzophosphol oxide followed by a simple transformation with exchange of substituents (and a homo-coupling reaction in one case) and a stereoselective reduction step furnished the corresponding phosphines in fair to good yield. Their relative and absolute configurations were determined by crystal structure analysis. It turned out that racemization of the phosphines through P-inversion takes place at ambient temperature and depends markedly on ortho substituents (104-114 kJ mol-1). In the case of the diphosphine, racemization can be suppressed when forming a chelate with Pd(II) or Ni(II) complexes.
Simple Preparation of (2,2'-Biphenylylene)phenylphosphine Oxide and Role of Triphenylphosphine Oxide as a Mediator for Formation of Biaryl Derivatives
Ogawa, Satoshi,Tajiri, Yoko,Furukawa, Naomichi
, p. 3182 - 3184 (2007/10/02)
(2,2'-Biphenylylene)phenylphosphine oxide (3) was prepared simply by the reaction of triphenylphosphine oxide (1) with phenyllithium and subsequently with aqueous hydrogen peroxide in acetic acid.The oxide 3 reacted with lithium diisopropylamide (LDA) and then with several elctrophiles to afford regiospecifically ortho-substituted compounds in moderate yields, which were converted to unsymmetrical 2- and 2,3'-substituted 1,1'-biaryls and triphenylphosphine oxide (1).
