Phosphorylation of alkyl‐2‐chloro‐2,3‐epoxyalkanoates with trialkyl phosphites: A novel approach to alkyl 2‐diethoxyphosphoryloxy‐2‐alkenoates

Alkyl 2‐chloro‐2,3‐epoxyalkanoates react with trialkyl phosphites to give mixtures of (E) and (Z) alkyl 2‐diethoxyphosphoryloxy‐2‐alkenoates instead of the expected alkyl 2‐oxo‐3‐dialkoxyphosphorylalkanoates. Thermal isomerization of the alkyl 2‐chloro‐2,3‐epoxyalkanoates to alkyl 3‐chloro‐2‐oxoalkanoates and subsequent Perkow reaction of the latter with trialkyl phosphites yields the same products but usually in different (E) to (Z) ratios. A likely mechanism for the unexpected reaction is discussed. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:115–119, 2000