November 1997 mercury lamp under continuous bubbling of ethylene gas, but the desired cyclobutane derivative 9 was not obtained and the starting 8 was recovered.” Therefore, we decided to construct the cyclobutane ring in a stepwise mode, and conjugate addition of an allyl group to the enone 8 was examined. The results are summarized in Table 1. When 8 was treated with allylmagnesium bromide in the presence of copper(I) bromide~~~dimethyl sulfide complex (CuBr- MeZS), ...
