From the imidazole. From the ester. competitive 1, 4 addition was observed at-78" C. However, when the reaction was conducted at 0" C, less than 10% of 1, 4 addition was detected (Scheme 11, Table I). Finally, in using, instead of the ester, the corresponding imidazole, pure 1, 2 addition was obtained at-78" C. Several a,@-unsaturated@-keto sulfoxides were prepared either from the corresponding esters at 0" C or from the ...
