Synthesis of chiral (phosphinoaryl)oxazolines, a versatile class of ligands for asymmetric catalysis
作者:Guido Koch、Guy C. Lloyd-Jones、Olivier Loiseleur、Andreas Pfaltz、Roger Prétôt、Silvia Schaffner、Patrick Schnider、Peter von Matt
DOI:10.1002/recl.19951140413
日期:——
Enantiomerically pure 2-[2-(diphenylphosphino)aryl]oxazolines are readily prepared from 2-bromobenzonitrile by transmetalation with BuLi, subsequent reaction with chloro-diphenylphosphine and conversion of the resulting phosphinoaryl nitrile to the oxazoline by treatment with a chiral amino alcohol in the presence of ZnCl2. An alternative synthesis is based on the orthometalation of 2-aryloxazolines
Chiral mercaptoaryl-oxazolines as ligands in enantioselective copper-catalyzed 1,4-additions of Grignard reagents to enones
作者:Zhou Qi-Lin、Andreas Pfaltz
DOI:10.1016/s0040-4020(01)89379-0
日期:1994.4
A series of chiral enantiomerically pure mercaptoaryl-oxazolines has been synthesized. Copper(I) thiolate complexes derived from these ligands proved to be efficient catalysts for the 1,4-addition of Grignard reagents to cyclic enones. Enantioselectivities increased in the sequence cyclopentenone (16–37% ee) < cyclohexenone (60–72% ee) < cycloheptenone (83–87% ee).