双环[2,2,1]庚-2,5-二烯和环辛-1,5-二烯(联膦)铑四氟硼酸酯在1个大气压下在甲醇或其他极性溶剂中与氢反应。初始产物可以是溶剂化的二氢化物或溶剂化物。根据磷化氢的结构,这两种物质之间的平衡差异很大。当配体为单膦时,二酐通常是稳定的产物,尽管(邻-甲氧基苯基)甲基苯基膦是一个例外。顺式螯合双膦通常形成对氢没有亲和力的溶剂合物。R-苯基双-二苯基膦基乙烷属于此类,但31其配合物的1 H NMR光谱表明单体和二聚体之间达到平衡,三乙胺的添加产生三聚体。反式螯合双膦具有更多的可变性,并且在双1,5-二苯基膦基戊烷的情况下,观察到许多复合物,包括需要CHH活化的复合物。
Diastereomeric chiral diphosphine chioro(η<sup>5</sup>-cyclopentadienyl)ruthenium(<scp>II</scp>) complexes and the crystal structure of [(S)RuCl(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>){(R)Ph<sub>2</sub>PCH(Me)CH<sub>2</sub>PPh<sub>2</sub>}]
Diastereomeric [RuCl(η5-C5H5)Ph2PCH(R)CH2PPh2}] chelate complexes (where R = CH3, cyclo-C6H11, or C6H5) form in nearly equimolar amounts in the displacementreaction of triphenylphosphine from [RuCl(η5-C5H5)(PPh3)2]. The diastereomers were separated by fractional crystallization. Diastereomeric composition at the equilibrium showed a low asymmetric induction (28–41%) by the optically active diphosphine ligand
非对映体将[RuCl(η 5 -C 5 H ^ 5)博士2 PCH(R)CH 2 PPH 2 }]螯合络合物(其中R = CH 3,环-C 6 H ^ 11,或C 6 H ^ 5)形式在近等摩尔量在从三苯基膦的置换反应将[RuCl(η 5 -C 5 H ^ 5)(PPH 3)2]。通过分级结晶分离非对映异构体。非对映体组成在手性钌原子上的旋光性二膦配体表现出低的不对称诱导(28-41%)。钌原子上的绝对构型对络合物的手性几乎没有影响,络合物的手性至少在可见区域似乎由螯合配体的手性构象支配。标题非对映体的晶体结构,[(小号)的RuCl(η 5 -C 5 H ^ 5)([R)PH 2 PCH(Me)的CH 2 PPH 2 }],进行了研究。是单斜的,空间群P 21, a = 9.688(3), b = 15.037(4), c = 10.556(2)Å,β= 113.54(2)°, Z =
Asymmetric synthesis of 1,2-bis(diphenylphosphino)-1-phenylethane via a chiral palladium template promoted hydrophosphination reaction
作者:Yi Zhang、Lulu Tang、Sumod A. Pullarkat、Fengli Liu、Yongxin Li、Pak-Hing Leung
DOI:10.1016/j.jorganchem.2009.06.024
日期:2009.10
mine was employed as the chiral auxiliary to promote the asymmetric hydrophosphination reactions between diphenylphosphine and (E) or (Z)-diphenylphosphinostyrene in high regio- and stereoselectivities at low temperature with triethyl amine as external base. Optically active free ligand (R)-1,2-bis(diphenylphosphino)-1-phenylethane was obtained in high yield subsequently. Mechanistic pathways explaining
Enantioselective Catalysts for the Diels–Alder Reaction between Methacrolein and Cyclopentadiene Based on the Chiral Fragment (η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)M(chiral diphosphane) (M = Rh, Ir)
作者:Daniel Carmona、Fernando Viguri、Ainara Asenjo、M. Pilar Lamata、Fernando Lahoz、Pilar Garcı́a-Orduña、L. A. Oro
DOI:10.1021/om200859z
日期:2011.12.26
The aqua complexes [(eta(5)-C5Me5)M(PP*)-(H2O)][SbF6](2) (M = Rh, Ir; PP* = chiral diphosphane) (1-10) are prepared and characterized. These complexes efficiently catalyze the Diels-Alder reaction between methacrolein and HCp with enantioselectivities of up to 96% e.e. The norphos complexes 9 and 10, which are obtained as diastereomeric mixtures of the two epimers at the metal, afford the highest e.e. values. The intermediate complexes [(eta(5)-C5Me5)M(PP*)-(methacrolein)] [SbF6](2) (11-20) are also isolated and characterized, including the molecular structure determination of the [(eta(5-CMe5)-Me-5)M(benphos)(methacrolein)][SbF6](2) (M = Rh (13), Ir (14)) derivatives. An NMR study of the reactivity of the metallic intermediates under catalytic conditions explains the high enantioselectivities achieved with the norphos systems.