作者：Alexandra M. Z. Slawin、J. Derek Woollins、Qingzhi Zhang
DOI：10.1039/b009074n
日期：——
N-Diphenylphosphinoamino acid methyl/ethyl esters RCH(NHPPh2)CO2R′
1a–1e were prepared in high yield from equimolar amounts of amino acid methyl/ethyl ester hydrochloride and chlorodiphenylphosphine. The reaction proceeds with configurational retention. Oxidation of 1a (R = R′ = CH3) with H2O2 or S8 leads to the N-diphenylphosphinoylalanine methyl ester 2a or N-diphenylthiophosphinoylalanine methyl ester 3a. 1a–1e function as monodentate ligands to [PtCl2(cod)], [RhCl(cod)]2 and [AuCl(tht)] to give cis-[PtCl2(1-P)2], [RhCl(cod)(1-P)] and [AuCl(1-P)]. Two equivalents of chlorodiphenylphosphine react with alanine methyl ester hydrochloride in CH2Cl2 to give N,N-bis(diphenylphosphino)alanine methyl ester, bdppal. This is an excellent bidentate ligand, the chelate complexes [MCl2(bdppal-P,P′)] (M = Pd or Pt) being prepared and studied by X-ray analysis. Oxidation at one P atom in bdppal with either H2O2 or S8 gives N-diphenylphosphino-N-diphenylphosphinoylalanine methyl ester, bdppalO, and N-diphenylphosphino-N-diphenylthiophosphinoylalanine methyl ester, bdppalS, respectively. bdppalO is very difficult to isolate but does react in situ with [PdCl2(cod)] to give [PdCl2(bdppalO-O,P)]. bdppalS reacts with [MCl2(cod)] (M = Pd or Pt) giving [MCl2(bdppalS-P,S)]. The dioxidised product N,N-bis(diphenylphosphinoyl)alanine methyl ester, bdppalO2, does not react with [MCl2(cod)] (M = Pd or Pt), whereas N,N-bis(diphenylthiophosphinoyl)alanine methyl ester, bdppalS2, reacts with [PdCl2(cod)] to give [PdCl2(bdppal-S,S′)]. All the compounds are chiral and have been fully characterised by microanalysis, IR, 31P-1H}, 1H NMR, and FAB+ mass spectroscopies, and in several cases structures are confirmed by X-ray analysis. The crystal structures described and those previously determined reveal the configurational retention of the reactions.
N-二苯基膦氨基酸甲酯/乙酯 RCH(NHPPh2)CO2R' 1a-1e 高产率地由等摩尔量的氨基酸甲酯/乙酯盐酸盐和氯化二苯基膦制备。反应过程中构型保持不变。1a（R = R' = CH3）的氧化采用 H2O2 或 S8，分别得到 N-二苯基膦酰丙氨酸甲酯 2a 或 N-二苯基硫代膦酰丙氨酸甲酯3a。1a-1e 作为单齿配体与[PtCl2(cod)]、[RhCl(cod)]2 和[AuCl(tht)]反应生成顺式-[PtCl2(1-P)2]、[RhCl(cod)(1-P)]和[AuCl(1-P)]。两当量的氯化二苯基膦与丙氨酸甲酯盐酸盐在 CH2Cl2 中反应生成 N,N-双(二苯基膦)丙氨酸甲酯，bdppal。这是一个极佳的双齿配体，螯合物[MCl2(bdppal-P,P')]（M = Pd 或 Pt）已制备并经 X 射线分析研究。bdppal 中的一个 P 原子被 H2O2 或 S8 氧化分别得到 N-二苯基膦-N-二苯基膦酰丙氨酸甲酯 bdppalO 和 N-二苯基膦-N-二苯基硫代膦酰丙氨酸甲酯 bdppalS。bdppalO 极难分离，但能与[PdCl2(cod)]现场反应生成[PdCl2(bdppalO-O,P)]。bdppalS 与[MCl2(cod)]（M = Pd 或 Pt）反应生成[MCl2(bdppalS-P,S)]。过氧化产物 N,N-双(二苯基膦酰)丙氨酸甲酯 bdppalO2 与[MCl2(cod)]（M = Pd 或 Pt）不反应，而 N,N-双(二苯基硫代膦酰)丙氨酸甲酯 bdppalS2 与[PdCl2(cod)]反应生成[PdCl2(bdppal-S,S')]。所有这些化合物都是手性的，并通过元素分析、红外、31P-1H}、1H NMR 和 FAB+质谱等手段进行了全面表征，在数个例子中通过 X 射线分析确认了结构。所述晶体结构及先前所测定的那些晶体结构揭示了反应中的构型保持现象。
