No abstract

Treatment of ynamides with silylcopper reagents resulted in silylcupration to afford (E)-β-silylenamides, after protonolysis, in good yields with high regio- and stereoselectivity. Reaction of ynamides having an allyl group on the nitrogen with Grignard reagents in the presence of a copper catalyst resulted in carbomagnesiation across the alkynyl unit and subsequent heating provided 4-pentenenitriles via aza-Claisen rearrangement.

Cobalt salts such as cobalt(II) chloride catalyze allylzincation reactions of 1-aryl-1-alkynes. The allylzincations proceed in a syn fashion to form 2-allyl-1-aryl-1-alkenylzinc species. Other internal alkynes such as 6-dodecyne or 2-nonyn-1-ol are much less reactive than 1-aryl-1-alkynes.

Treatment of N-allyl-N-(phenylethynyl)arenesulfonamides with Grignard reagents under copper catalysis resulted in carbomagnesiation across the alkynyl parts. The carbomagnesiations yielded 2-magnesio-3-aza-1,5-hexadienes, which underwent the aza-Claisen rearrangement upon heating. The rearrangement followed by elimination of the arenesulfonyl groups provided 2,2-disubstituted 4-pentenenitriles.