Alkynones catalytic generation

Scheme 19 Catalytic generation of alkynones and subsequent addition-cyclocondensation...

The distinctive feature of the catalytic generation of alkynones under modified Sonogashira conditions is the usage of one stoichiometrically necessary equivalent of triethylamine per bond forming reaction [47, 48]. Since the base is inevitably consumed in binding the liberated hydrogen halide the reaction medium is... 

The catalytic generation of alkynones and chalcones by palladium catalyzed reactions is an entry to sequential, consecutive, and domino transformations and opens new routes to heterocycles by consecutive coupling-cyclocondensation or Cl-cyclocon-densation sequences. The advantages are not only the compatibility of similar reaction conditions but also the tunable reaction design that allows the combination of several organic and organometallic elementary reactions to new diversity oriented syntheses. Future developments will address also sequentially catalyzed processes... 

Propynones and 3-butyne-1,2-diones are densely substituted bi- and trifunctional electrophiles that can be generated by Pd-Cu- or by Cu-catalyzed all nylation. The mild and general reaction conditions allow a straightfonward entry to consecutive multicomponent syntheses of heterocycles conducted in a one-pot fashion. This overview presents recent advances in the catalytic generation of alkynones and alkynediones and their application to multicomponent syntheses of 19 classes of heterocycles in a diversity-oriented fashion. 

The concept of alkyne activation by Sonogashira coupling was successfully extended to the in situ generation of alkynones that are highly reactive and versatile synthetic equivalents of 1,3-dicarbonyl compounds. Interestingly, ynones can be readily synthesized in a catalytic fashion by Sonogashira coupling of an acyl chlor-... 

Alonso DA, Najera C, Pacheco MC (2004) Synthesis of ynones by palladium-catalyzed acylation of terminal alkynes with acid chlorides. J Org Chem 69 1615-1619 D Souza DM, Miiller TJJ (2008) Catalytic alkynone generation by Sonogashira reaction and its application in three-component pyrimidine synthesis. Nat Protoc 3 1660-1665 Karpov AS, Miiller TJJ (2003) A new entry to a three component pyrimidine synthesis by TMS-ynones via sonogashira-coupling. Org Lett 5 3451-3454... 

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