Catalytic Asymmetric Cyano-Ethoxycarbonylation Reaction of Aldehydes using a YLi<sub>3</sub>Tris(binaphthoxide) (YLB) Complex: Mechanism and Roles of Achiral Additives
Full details of a catalytic asymmetric cyano-ethoxycarbonylation reactionpromoted by a heterobimetallicYLi3tris(binaphthoxide) complex (YLB 1), especially mechanisticstudies, are described. In the cyanation reaction of aldehydes with ethyl cyanoformate, three achiral additives, H2O, tris(2,6-dimethoxyphenyl)phosphine oxide (3a), and BuLi, were required to achieve high reactivity and enantioselectivity
NMR studies of proton transfer in 1∶1 tris(trimethoxyphenyl)phosphine oxide–phenol complexes
作者:Claudia M. Lagier、Alejandro C. Olivieri、Robin K. Harris
DOI:10.1039/a802219d
日期:——
substituents attached to the phenol. Thus, the chemicalshift of the hydroxylic hydrogen for complexes in solution varies from lower frequencies (8.2 ppm) for phenolderivatives of high pKa (e.g. 10.2) to higher frequencies (11.9 ppm) as the pKa of the phenol decreases. However, for highly acid phenols such as picric acid (pKa = 0.38), the signal moves to lower frequencies again as a result of the shielding
研究了三(三甲氧基苯基)氧化膦(TMPPO)与八种不同取代酚之间的加合物中的氢转移过程,包括溶液和固态。为此目的,已记录了这些配合物的1 H和31 P NMR溶液状态光谱。氢键质子的1 H化学位移和氧化膦的31 P化学位移很大程度上受连接在苯酚上的取代基的影响。因此,对于复合物在溶液中的羟基氢的化学位移从高P的苯酚衍生物较低频率(8.2 ppm的)变化ķ一个(例如10.2)到更高的频率(11.9 ppm的)作为p ķ一个酚的降低。但是,对于强酸酚(例如苦味酸)(p K a = 0.38),由于TMPPO残基的氧原子产生的屏蔽作用,信号再次移至较低频率。另一方面,溶液中配合物的31 P化学位移以相同的趋势变化:随着取代苯酚的p K a降低,磷信号移动到更高的频率。还通过高分辨率CPMAS 13 C和31 P NMR实验研究了固态的8种配合物。也有证据表明固态氢转移过程会导致31P屏蔽张量,
The Trityl‐Cation Mediated Phosphine Oxides Reduction
Reduction of phosphineoxides into the corresponding phosphines using PhSiH3 as a reducing agent and Ph3C+[B(C6F5)4]− as an initiator is described. The process is highly efficient, reducing a broad range of secondary and tertiary alkyl and arylphosphines, bearing various functional groups in generally good yields. The reaction is believed to proceed through the generation of a silyl cation, which reaction
描述了使用PhSiH 3作为还原剂和Ph 3 C + [B(C 6 F 5 ) 4 ] -作为引发剂将氧化膦还原成相应的膦。该方法效率很高,可以减少各种带有各种官能团的仲和叔烷基和芳基膦,收率通常很高。据信,该反应通过生成甲硅烷基阳离子进行,该阳离子与氧化膦反应提供鏻盐,进一步被硅烷还原以提供所需的膦和硅氧烷。
Investigation of the intermediates in the oxidation of a bulky arylphosphine ligand with ferric chloride
作者:Kim R. Dunbar、Anne Quillevéré
DOI:10.1016/s0277-5387(00)81763-5
日期:1993.4
The syntheses, spectroscopic properties and structures of iron(II) and iron(III) complexes prepared by reactions of ferric chloride with the tertiaryphosphine ligand tris(2,4,6-trimethoxyphenyl)phosphine (TMPP) are described. The novel diferrous chloride salt [H-TMPP]2[Fe2Cl6] (1) was prepared by the reaction of anhydrous ferric chloride with 1 equivalent of TMPP in benzene or diethyl ether. This redox