Substituted alkenyl acrylamides

Substituted alkenyl and aryl acrylamides 308 and 310 undergo electro-cyclic ring closure at 800 °C to produce the dihydropyridone derivatives 309 and 311, respectively, in moderate yields (Scheme 62 2002SC875). The unsaturated ester 312 also imdergoes electrocyclization followed by in situ aromatization to give the tricyclic product 313 (20060BC407). 

Japanese workers prepared examples of 2-alkenyl-4,5-oxazolediones 40a and 40b, which are key intermediates in the synthesis of alkenoyl isocyanates 41a and 41b (Scheme 6.13). These reactive monomers are precursors to a variety of functionalized polymers including instantaneously curable compositions. Thus, reaction of oxalyl chloride with acrylamide 39a or methacrylamide 39b affords 40a and 40b isolated as hydrochloride salts in high yields. Subsequent decomposition of the 2-alkenyl-4,5-oxazolediones in the presence of a metal halide or synthetic zeolite affords 41a and 41b contaminated with varying amounts of 42a and 42b. The synthesis and reactions of other 2-substituted 4,5-oxazolediones have been described independently by Speziale and co-workers ° and Sasaki and co-workers. ... 

Radical carbonylation reaction serves as a powerful tool for the synthesis of a range of carbonyl compounds. Radical carbonylation has been successfully applied to the synthesis of functionalized ketones from alkyl, aryl, and alkenyl halides.The radical aminocarbonylation reaction of alkynes and azaenynes provided efficient routes to 2-substituted acrylamides, lactams, and pyrrolidinones. For example, the aminocarbonylation of 4-pentyn-l-yl acetate 318 initiated by tributyltin hydride (Bu"3SnH) (30mol%) with AIBN (20mol%) gave acrylamide 325 in 92% yield (Scheme 43).A proposed mechanism starts from the addition of tributyltin radical 319 to alkyne... 

C-H activation is an important and rapidly developing area of dendralene synthesis. In very recent years, several C2-C3 bond forming approaches to dendralenes involving C-H activation have been reported. In 2013, Glorius and coworkers developed a Rh(III)-catalyzed, Heck-type alkenyl C-H activation and coupling reaction with allenyl carbinol carbonates 205 and acrylamides 206 (Scheme 1.33) [157]. This new reaction performs well for the synthesis of highly substituted [3]dendralenes. 

Furans substituted at the 2-position efficiently undergo coupling to give 2-alkenylated furans in good yields (Scheme 2.20). Selected alkenes as the coupling partner are acrylates, acrylamides, methylvinylketone, acry-laldehyde, acrylonitrile, and styrenes. 

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