Synthesis of Ferrocene Oxazoline N,O ligands and Their Application in Asymmetric Ethyl- and Phenylzinc Additions to Aldehydes.
The synthesis of a range of novel gem-disubstituted ferrocene-oxazoline ligands and their application in both the asymmetric ethyl- and phenylzinc additions to aldehydes is reported. These studies reveal that gem-disubstitution of i-Pr-containing ferrocene oxazoline ligands results in increased enantioselectivity compared to their unsubstituted counterparts. Utilizing zinc catalysis, these ligands provided a wide range of secondary alcohols in yields of up to 93% with ee's of up to >99%. An interesting crystal structure of a ferrocene oxide-lithium tetramer showing lithium-nitrogen coordination in the solid state is also presented.
Centre for Synthesis and Chemical Biology, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland.
Chris
C
Nottingham
Centre for Synthesis and Chemical Biology, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland.
Robert
R
Benson
Centre for Synthesis and Chemical Biology, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland.
Helge
H
Müller-Bunz
Centre for Synthesis and Chemical Biology, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland.
Patrick J
PJ
Guiry