Synthesis of new derivatives of copper complexes of Josiphos family ligands for applications in asymmetric catalysis
作者:R. Oost、J. Rong、A. J. Minnaard、S. R. Harutyunyan
DOI:10.1039/c4cy00180j
日期:——
A series of new copper complexes containing chiral ferrocenyl diphosphine ligands of the Josiphos family have been prepared. These complexes have been studied in the catalytic asymmetric 1,2-addition of Grignard reagents to enones and aromatic ketones. Variation of the electronic and steric properties of the ligand resulted in a positive effect in the regio- and enantioselectivity of Grignard reagents
Reactions of Et<sub>3</sub>ZnLi with Ketones: Electronic and Steric Effects<sup>1</sup>
作者:Curtis A. Musser、Herman G. Richey
DOI:10.1021/jo000630j
日期:2000.11.1
Toluene solutions of composition Et3ZnLi react rapidly with aldehydes and ketones to form addition products. Et3ZnNa and Et3ZnK solutions react readily with the same substrates although metalation, as well as addition, is significant with substrates having alpha -hydrogens. The Et3ZnM solutions react with 2-cyclohexenone to give mainly the 1,4-addition product. Relative rates of addition of Et3ZnLi to substituted acetophenones give a Hammett rho of 2.78. Addition of Et3ZnLi to acetophenone is sf owed significantly by alpha and ortho methyl substituents; relative rates of addition to acetophenone, o-methylacetophenone, and tert-butyl phenyl ketone are 1.00, 0.012, and 0.003.
Kinoshita, Tomomi; Takemoto, Masaki; Shibayama, Koichi, Journal of Chemical Research, Miniprint, 1993, # 8, p. 2153 - 2174