Efficient enantiodiscrimination of chiral monophosphine oxides and boranes by phosphorus coupled 13C NMR spectroscopy in the presence of chiral ordering agents
摘要:
The synthesis of new chiral phospholanes via the corresponding oxides or boranes is reported and the analytical potential of C-13-{H-1} NMR spectroscopy in weakly ordering polypeptide liquid crystalline phases in view to differentiate between enantiomers of these chiral phosphines precursors is explored. In particular results involving organic solutions of poly-gamma-benzyl-L-glutamate (PBLG) and poly-epsilon-carbobenzyloxy-L-lysine (PCBLL) are described. This NMR approach allows determination of the enantiomeric composition, and provides therefore a new efficient alternative to classical methods usually used to analyze this class of compounds. A description of various spectral enantiodifferentiation patterns expected to be observed using C-13-{H-1} NMR of enantiomers having a spin-1/2 heteroatomic nucleus, embedded in a chiral liquid crystal is presented. (C) 2003 Elsevier Science Ltd. All rights reserved.
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
Pseudo-C2-symmetric chiral phosphorus ylide is designed and synthesized for the enantioselective preparation of allenic esters, amides, ketone, and nitrile. Up to 92% ee is achieved.
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.