Enantiopure P‐aryl‐2,5‐diphenylphospholanes and its corresponding P‐aryl‐phospholanium salt appear as very efficientligands for rhodium‐catalyzed asymmetrichydrogenation reaction with similar activities and enantioselectivities. The hydrogenation product was obtained in good enantiomeric excesses (up to 93 % ee) in only few minutes under an atmospheric pressure of dihydrogen. The excellent activity
(S,S)-1,2,5-Triphenylphospholanium tetrafluoroborate salt 2 was conveniently used as chiral ligand precursor in rhodium-catalyzed asymmetrichydrogenation of methyl (Z)-2-acetamidocinnamate. 31P NMR showed the existence of a solvent-dependent equilibrium between the salt and the free phosphine.
(S,S)-1,2,5-三苯基磷鎓四氟硼酸盐2方便地用作铑催化的(Z)-2-乙酰氨基二十二酸甲基酯的不对称氢化中的手性配体前体。31 P NMR表明盐和游离膦之间存在溶剂依赖性平衡。
Enantioselective synthesis of allenic esters via an ylide route
作者:Chuan-Ying Li、Xiu-Li Sun、Qing Jing、Yong Tang
DOI:10.1039/b603659g
日期:——
Pseudo-C2-symmetric chiral phosphorus ylides have been designed and synthesized for the enantioselective preparation of allenicesters, and up to 92% ee has been achieved.