An Efficient Synthesis of (−)-Chloramphenicol via Asymmetric Catalytic Aziridination: A Comparison of Catalysts Prepared from Triphenylborate and Various Linear and Vaulted Biaryls
摘要:
[GRAPHICS]The antibiotic (-)-choramphenicol has been synthesized in only four steps from p-nitro-benzaldehyde in optically pure form from an asymmetric catalytic aziridination reaction with a chiral catalyst prepared from triphenylborate and the (R)-VAPOL ligand. Catalysts generated from the VAPOL and VANOL ligands give much higher asymmetric induction than do catalysts prepared from 6,6'-diphenylVAPOL, BINOL, and BANOL ligands.
Organocatalytic Aziridine Synthesis Using F<sup>+</sup> Salts
作者:Sean P. Bew、Shirley A. Fairhurst、David L. Hughes、Laurent Legentil、John Liddle、Paolo Pesce、Sanket Nigudkar、Martin A. Wilson
DOI:10.1021/ol901784m
日期:2009.10.15
This paper describes a unique application of the fluoronium cation (F+) as an organocatalyst for mediating the reaction between N-substituted imines and ethyl diazoacetate affording excellent yields of N-substituted aziridines.