Unusual Approach to Branched 3-Alkynylamides and to 1,5-Dihydropyrrol-2-ones

Rare carboxamide branched alkynes such as 11a can be readily obtained by reaction of the electrophilic 4-alkylidene isoxazolinones with isocycanides followed by nitrosative cleavage of the heterocyclic ring. N-Iodosuccinimide induced ring closure in the presence of a nucleophile results in the formation of new iodopyrrolinones such as 16c.