A useful regiospecific synthesis of unsymmetrical'isoxazoles from oximes is described in a recent publication from this laboratory. 2 The method is illustrated by the converaion of benzylacetone oxime (1) to the isoxazole (4, 91% overall yield distilled) by deprotonation of 1 with n-BuLi to form the syn-dilithio salt (21, which is acylated by DMF to give 3. The latter subsequently is cyclized to 4 with hot aqueous acid. In a variant of the above route, the ...
