Palladium-Catalyzed Cyclization of Alkynoic Acids To Form Vinyl Dioxanones Bearing a Quaternary Allylic Carbon
作者:Yohei Ogiwara、Kazuya Sato、Norio Sakai
DOI:10.1021/acs.orglett.7b02572
日期:2017.10.6
A palladium-catalyzed intramolecular reaction of carboxylic acids and alkynes in a novel cyclization manner was developed. This unique cyclization efficiently provided a wide range of complex ring systems—vinyl dioxanones bearing a quaternary allylic carbon. Mechanistic studies suggest an allenyl carboxylate as an intermediate.
The unique cyclization of benzamide derivatives that contain an alkyne by a Pd(0)/dialkyl(biaryl)phosphine catalytic system is reported. The reaction efficiently provides a variety of six-membered N-heterocyclic compounds that contain a fully substituted carbon center without the need for a stoichiometric additive. Mechanistic studies suggest that this unprecedented cyclization starts with the cleavage
Enantioselective tandem formation and [2,3]‐sigmatropic rearrangement of cyclic propargylic oxonium ylides catalyzed by dirhodium(II) tetrakis[<i>N</i>‐phthaloyl‐(<i>S</i>)‐<i>tert</i>‐leucinate]
rearrangement of propargylic oxonium ylides generated by catalytic diazo decomposition. Catalysis of α-diazo-ß-keto esters 4a—g using dirhodium(II) tetrakis[N-phthaloyl-(S)-tert-leucinate] in toluene has led to the virtually exclusive formation of benzofuran-3-ones bearing an allenic group with up to 79% ee.
Gold promoted arylative cyclization of alkynoic acids with arenediazonium salts
作者:Ulises A. Carrillo-Arcos、Susana Porcel
DOI:10.1039/c7ob02447a
日期:——
Alkynoicacids derived from salicylic acid and analogues undergo arylative cyclization with arenediazonium salts promoted by gold in the absence of external ligands. The reaction is thermally induced and proceeds even in the absence of light. A difference in regioselectivity has been found compared with that observed in the cycloisomerization process of the same type of compounds.