Toshikazu Hirao, Takashi Fujii, Toshihiko Tanaka and Yoshiki Ohshiro
J. Chem. Soc., Perkin Trans. 1, 1994, 3-4
DOI:
10.1039/P19940000003,
Paper
2, 2-Dichlorocyclobut-3-enones undergo VO(OEt)Cl2-induced ring-opening oxidation in ethanol to give ethyl 2,4,4-trichlorobut-3-enoates regioselectively.