Reactions of Heterocumulenes with Organometallic Reagents: IX. Synthesis and Rearrangements of N-Allyl-and N-[2-(Vinyloxy)ethyl]-3-butenethioamides and -1-(methylsulfanyl)-3-buten-1-imines

Reactions of allyl and 2-(vinyloxy)ethyl isothiocyanates with alyylmagnesium bromide (THF-Et₂O, 20-30°C, 1-3 h) after hydrolysis or alkylation of adducts afforded respectively N-allyl- and N-2-(vinyloxy)ethyl]-3-butenethioamides or N-allyl- and N-2-(vinyloxy)ethyl]-1-(methylmercapto)-3-buten-1-imines. The reaction carried out in ethyl ether yielded instead of Nt-allyl-3-butenethioamide its isomer N-allyl-2-butenethioamide that cleanly isomerized in the system KOH-DMSOH₂O into N-(1-propenyl)-2-butenethioamide. N-2-(vinyloxy)ethyl]-3-butenethioamide suffers a prototropic rearrangement into N-2-(vinyloxy)ethyl]-2-butenethioamide only in the system