β-Acylvinyl Anion and Dianion Equivalents: Lithiation of 1-[(2<i>EZ</i>)-3-Chloroprop-2-enyl]-1<i>H</i>-1,2,3-benzotriazole: Preparation and Elaboration of 1-(2-Oxiranylvinyl)-1<i>H</i>-benzotriazoles

The allyllithium generated from 1-[(2EZ)-3-chloroprop-2-enyl]-1H-1,2,3-benzotriazole (5) and LDA, in the presence of HMPA, reacts with enolizable and nonenolizable carbonyls solely at the CCl terminus to give 1-(2-oxiranylvinyl)benzotriazoles 6a−g in 61−82% yields. Allyllithiums generated from 6a,c reacted exclusively at the CBt terminus to give 10a−d in 68−88% yields. Acidic hydrolysis of (oxiranylvinyl)benzotriazoles 6a−g and 10a−d provided 4-hydroxyalk-2-en-1-one derivatives 12a,b,c,e,g, 13a−d, and furan 14 in 54−86% yields.