Catalytic decarbonylation, hydroacylation, and resolution of racemic pent-4-enals using chiral bis(di-tertiary-phosphine) complexes of rhodium(I)
作者:Brian R. James、Charles G. Young
DOI:10.1016/0022-328x(85)87377-0
日期:1985.4
Attempts to decarbonylate racemic aldehydes catalytically using rhodium(I) complexes containing chiral di-tertiary-phosphine ligands are described. Incorporation of an alkenic moiety into the aldehyde, for subsequent probing of induced asymmetry by chiral shift reagents, leads instead to formation of optically active hydroacylated products via kinetic resolution of the precursor racemic aldehyde. For example
描述了尝试使用含有手性二叔膦配体的铑(I)配合物催化外消旋醛的羰基化。为了随后通过手性转移试剂探测诱导的不对称性,将醛基部分掺入醛中,而是通过前体外消旋醛的动力学拆分而导致形成光学活性的氢酰化产物。例如,用[Rh(S,S -chiraphos)2处理,(RS)-2-甲基-2-苯基戊-4-烯醛(1a)的产率具有(-)-(S)旋光异构体的最多69%ee的] Cl,2-甲基-2-苯基环戊酮和剩余的未反应醛,可能是对映体纯的(-)-(R)形式。将该环化反应延伸至3,3-二取代的戊-4-烯类似地提供了光学活性的3,3-二取代的环戊酮的合成。还观察到脱羰副产物。1a中的那些以E-和Z -2-苯基戊-2-烯的形式出现。Rh(chiraphos)(solvent)2 +也可催化1a的环化反应,但ee较低