Camus Jean-Michel, Andrieu Jacques, Poli Rinaldo, Richard Philippe, Baldoli Clara, Maiorana Stefano
Laboratoire de Synthèse et d'Electrosynthèse Organométalliques, UMR 5632, Université de Bourgogne, Faculté des Sciences Gabriel, 6 boulevard Gabriel, 21000 Dijon, France.
Inorg Chem. 2003 Apr 7;42(7):2384-90. doi: 10.1021/ic025588k.
The diastereoselective addition of Ph(2)PH to the chiral ortho-substituted eta(6)-benzaldimine complexes (eta(6)-o-X-C(6)H(4)CH=NAr)Cr(CO)(3) (1, X = MeO, Ar = p-C(6)H(4)OMe; 2, X = Cl, Ar = Ph) leads to the formation of the corresponding chiral aminophosphines (alpha-P,N) Ph(2)P-CH(Ar(1))-NHAr(2) (3, Ar(1) = o-C(6)H(4)(OCH(3))[Cr(CO)(3)], Ar(2) = p-C(6)H(4)OCH(3); 4, Ar(1) = o-C(6)H(4)Cl[Cr(CO)(3)], Ar(2) = Ph) in equilibrium with the starting materials. The uncomplexed benzaldimine (o-ClC(6)H(4)CH=NPh), 2', analogously produces an equilibrium amount of the corresponding aminophosphine Ph(2)P-CH(Ar(1))-NHAr(2) (4', Ar(1) = o-C(6)H(4)Cl, Ar(2) = Ph). Depending on the equilibrium constant, the subsequent addition of (1)/(2) equiv of RhCl(COD) (COD = 1,5-cyclooctadiene) leads to either Ph(2)PH oxidative addition in the case of 3 or to the corresponding [RhCl(COD)(alpha-P,N)] complexes [RhCl(COD)(Ph(2)P-CH[o-C(6)H(4)Cl[Cr(CO)(3)]]-NHPh)] (5) and [RhCl(COD)(Ph(2)P-CH(o-C(6)H(4)Cl)-NHPh)] (5') in the cases of the aminophosphines 4 and 4'. The addition of the latter ligands, as racemic mixtures, to (1)/(4) equiv of Rh(CO)(2)Cl leads to the [RhCl(CO)(alpha-P,N)(2)] complexes [RhCO(Ph(2)P-CH[o-C(6)H(4)Cl[Cr(CO)(3)]]-NHPh)(2)Cl] (7) or [RhCO(Ph(2)P-CH(o-C(6)H(4)Cl)-NHPh)(2)Cl] (7') as mixtures of (R(C),S(C))/(S(C),R(C)) and (R(C),R(C))/(S(C),S(C)) diastereomers. The rhodium complexes 5 and 7' have been fully characterized by IR and (31)P NMR spectroscopies and X-ray crystallography. These compounds exhibit intramolecular Rh-Cl.H-N interactions in the solid state and in solution. The stability of the new rhodium complexes has been studied under different CO pressures. Under 1 atm of CO, 5 is converted to an unstable complex [RhCl(CO)(2)(alpha-P,N)], 6, which undergoes ligand redistribution leading to 7 plus an unidentified complex. This reaction is inhibited under higher CO or syngas pressure, as confirmed by the observation of the same catalytic activity in hydroformylation when styrene was added to a catalytic mixture that was either freshly prepared or left standing for 20 h under high CO pressure.
将二苯基膦（Ph₂PH）非对映选择性加成到手性邻位取代的η⁶ - 苯甲醛亚胺配合物（η⁶ - o - X - C₆H₄CH = NAr）Cr(CO)₃（1，X = MeO，Ar = p - C₆H₄OMe；2，X = Cl，Ar = Ph）上，会生成相应的手性氨基膦（α - P，N）Ph₂P - CH(Ar₁) - NHAr₂（3，Ar₁ = o - C₆H₄(OCH₃)[Cr(CO)₃]，Ar₂ = p - C₆H₄OCH₃；4，Ar₁ = o - C₆H₄Cl[Cr(CO)₃]，Ar₂ = Ph），并与起始原料处于平衡状态。未配位的苯甲醛亚胺（o - ClC₆H₄CH = NPh），即2'，类似地会生成相应氨基膦Ph₂P - CH(Ar₁) - NHAr₂（4'，Ar₁ = o - C₆H₄Cl，Ar₂ = Ph）的平衡量。根据平衡常数，随后加入（1）/（2）当量的[RhCl(COD)]₂（COD = 1,5 - 环辛二烯），对于3的情况会导致Ph₂PH发生氧化加成，而对于氨基膦4和4'的情况则会生成相应的[RhCl(COD)(α - P，N)]配合物[RhCl(COD)(Ph₂P - CH[o - C₆H₄Cl[Cr(CO)₃]] - NHPh)]（5）和[RhCl(COD)(Ph₂P - CH(o - C₆H₄Cl) - NHPh)]（5'）。将后一种配体以外消旋混合物的形式加入（1）/（4）当量的[Rh(CO)₂Cl]₂中，会生成[RhCl(CO)(α - P，N)₂]配合物[RhCO(Ph₂P - CH[o - C₆H₄Cl[Cr(CO)₃]] - NHPh)₂Cl]（7）或[RhCO(Ph₂P - CH(o - C₆H₄Cl) - NHPh)₂Cl]（7'），它们是（R(C)，S(C)）/（S(C)，R(C)）和（R(C)，R(C)）/（S(C)，S(C)）非对映异构体的混合物。铑配合物5和7'已通过红外光谱、³¹P核磁共振光谱和X射线晶体学进行了全面表征。这些化合物在固态和溶液中均表现出分子内Rh - Cl···H - N相互作用。已在不同的CO压力下研究了新型铑配合物的稳定性。在1个大气压的CO下，5会转化为不稳定的配合物[RhCl(CO)₂(α - P，N)]，即6，它会发生配体重新分布，生成7以及一种未鉴定的配合物。当将苯乙烯加入到新鲜制备或在高CO压力下放置20小时的催化混合物中时，在氢甲酰化反应中观察到相同的催化活性，这证实了在较高的CO或合成气压力下该反应受到抑制。
