As a part of our program directed toward the synthesis of highly substituted optically active synthons bearing vicinally substituted quaternary and tertiary carbon centers, [1] we faced the problem of the low reactivity of alkyl and aryl crotonates in the Michael reaction of chiral imines. [2] In this respect, we selected the corresponding ethylidene malonates 2 (Scheme [1] ) [3] as synthetic equivalents of alkyl crotonates possessing an enhanced reactivity. Indeed, alkylidene ...
