Intramolecular cyclization of β-alkynylpropanamides to γ-alkylidene- γ-butyrolactams

Article abstract of DOI:10.1016/S0040-4039(98)00520-6

A general method for the base-catalized intramolecular cyclization of β-alkynylpropanamides 1 to γ-alkylidene-γ-butyrolactames 2 (and 3) was established. Reactions of β-alkynylamides 1c-h, possessing alkyl groups at the terminal acetylenes, in the presence of a catalytic amount of LiN(TMS)₂/AgOTf (= 2:1) in toluene gave exclusively (Z)-alkylidenelactames 2c-h in good yields.