Acetophenones alkynes from

Hydration of terminal alkynes to methyl ketones is a valuable synthetic transformation. The reverse conversion, viz. from a methyl ketone to an alkyne can also be a useful transformation. One of the most effective (but largely neglected) procedures for the conversion ArCOMe— ArC =CH has been shown to be the reaction of the acetophenone with two equivalents of POCI3 in DMF followed by treatment of the intermediate thus produced with a hot solution of sodium hydroxide in aqueous dioxane. The method can be used to prepare mono-, di- and triethynylarenes in 30-50% yield. 

Oxidation of the complex prepared from acetophenone and benzylmanganese pentacarbonyl with trimethylamine oxide, followed by the addition of an alkyne R C=CR (R = H, alkyl, EtO or Ph R =H, alkyl, Ph, MesSi or C02Et), affords indenols 470 in which the bulkier substituent of the alkyne is attached to C(2). Analogous products 471 are obtained from a-tetralone. ... 

Enaminothiones, prepared from acetophenones by Vilsmeier methodology, give substituted 2//-thiopyrans on reaction with various dienophiles as a consequence of elimination of dimethylamine (94JPR434). 3-Thioacetyindoles behave in a similar manner and yield thiopyrano[4,3-l ]indoles (94H725). 3-Aryl-2-cyanothioacrylamides form 4-aryl-4W-thiopyrans on treatment with activated alkynes (94JCS(P1)989). 

Rhodium(III)-catalyzed oxidative coupling of arylsulfonic acids with internal alkynes gives access to a variety ofsultones (Scheme 87) (14CC9776). Other derivatives arise from the cascade self-condensation of acetophenone derivatives and sulfonation reactions, promoted by methylsulfonylimidazo-lium triflate hydrochloride (14SL827). 

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