Phosphonate Modification for a Highly (Z)-Selective Synthesis of Unsaturated Esters by Horner-Wadsworth-Emmons Olefination
作者:Fran�ois P. Touchard
DOI:10.1002/ejoc.200400769
日期:2005.5
The Horner–Wadsworth–Emmons (HWE) reaction of various ethyl diarylphosphonoacetates with benzaldehyde, cyclohexane carboxaldehyde and octanal is reported. Selectivities of up to 98 % at –78 °C are obtained with the three substrates. Among all the phosphonates prepared, the reagent based on 2-tert-butylphenol proved to be especially efficient, with Z/E ratios close to 95:5 at 0 °C. It appears thus to