Acylation of thermal acetylenes

Synthesis of Ynones and Recent Application in Transition-Metal-Catalyzed Reactions

“…1). 16,17 Only 1 mol% of copper(I) iodide was required, thereby allowing low catalyst loading of a non-precious metal. The reaction generally involved high reaction temperatures to provide ynones with moderate to good yields (50-72%).…”

“…Also, as triethylamine was the solvent, the solubility of some substrates was decreased; decomposition of base-sensitive functional groups also occurred. The research reported by both Zanina 16 and Kundu 1c offer a valuable alternative to traditional Sonogashira conditions for ynone preparation (vide infra).…”

Pd/Cu-Catalyzed Synthesis of Internal and Sila-Ynones by Direct Selective Acyl Sonogashira Cross-Coupling of Carboxylic Acids with Terminal Alkynes

“…The use of toxic CO gas leads to difficulty in operation and safety issues. Acyl halides have been used as the acyl source to produce ynones, despite the harsh reaction conditions using hard organometallics and severely limited substrate scope owing to the low stability of the C­(acyl)–X bond to acylative cross-coupling conditions. , In recent years, other activated precursors have also been used in reactions with terminal alkynes to produce ynones in moderate to good yields. − …”

Synthesis of substituted benz[g]indole-6,9-diones and benzo[h]quinoline-7,10-diones by heterocyclization of 6-alkynyl-5-amino-1,4-naphthoquinones

“…In addition, ketone 7 was synthesized by condensa tion of iodide 2 with cuprous benzoylacetylide 19 and by benzoylation of ethynylnaphthoquinone 4e. 20 Unfortu nately, the acetylide method is applicable only in certain cases because of instability of many acylacetylides. As for catalytic acylation, it is complicated by side reactions and gives products in low yields.…”