New chiral crown ethers derived from camphor and their application to asymmetric Michael addition. First attempts to rationalize enantioselection by AM1 and AMBER calculations
作者:Ernesto Brunet、Ana M. Poveda、Dolores Rabasco、Enrique Oreja、Luis M. Font、Manohar Singh Batra、Juan C. Rodriguez-Ubis
DOI:10.1016/s0957-4166(00)86246-1
日期:1994.5
optically active crownethersderivedfrom (1R)-(+)-camphor is described. The mechanism of their catalytic effect upon the Michael addition of phenylacetate to acrylate is discussed in terms of kinetic vs. thermodynamic control in the formation of the catalytic ion-pair complexes. The relative basicity of the complexes formed between the alkaline metals and the unprotonated chiralcrownethers plays an important