DABCO-catalyzed C–C bond formation reaction between electron-deficient alkynes and 1,3-dicarbonyl compounds
作者:Hua Cao、Haiping Zhong、Yuanguang Lin、Liuqing Yang
DOI:10.1016/j.tet.2012.03.047
日期:2012.5
excellent catalyst DABCO has been found to catalyze C–C bond formation reaction between activated methylenes and alkynes. The transformation has provided a facile route for the synthesis of 2H-pyran-2-ones or unsaturated alkenoicacidester derivatives and explored the new possibilities of N-catalysts for Michael addition of nucleophiles with alkynoates.
Hydroalkylation leading to heterocyclic compounds. Part 1: New strategies for the synthesis of polysubstituted 2H-pyran-2-ones
作者:Wei-Bing Liu、Huan-Feng Jiang、Chun-Li Qiao
DOI:10.1016/j.tet.2008.12.069
日期:2009.3
Polysubstituted 2H-pyran-2-ones and 5,6-dihydro-2H-pyran-2-ones were synthesized via the MCRs initiated by the hydroalkylation of alkynoates with activated methylenes. Under the optimized reaction conditions, the desired products were obtained in 47–88% isolated yields. The experimental results showed that the groups on activated methylenes act important roles in the nucleophilic attack fashion.
Synthesis of Polysubstituted α-Pyrones Using Zinc-Catalyzed Addition-Cyclization Reactions
作者:Wei-Bing Liu、Cui Chen、Qing Zhang、Zhi-Bo Zhu
DOI:10.1002/jhet.1698
日期:2014.9
Various polysubstituted α‐pyrone derivatives have been directly synthesized via a hydroalkylation of Michael additional reaction following a cyclized process catalyzed by the Lewis acid of Zn(OAc)2. This protocol provides a new convenient and step‐economical route to construct heterocycles. Fourteen examples are obtained from easily available materials with moderate to good yields.
ReBr(CO)5-catalyzed sequential addition–cyclization of 1,3-dicarbonyl compounds with electron-deficient internal alkynes affording trisubstituted 2H-pyran-2-ones
作者:Wen-Guo Zhao、Ruimao Hua
DOI:10.1016/j.tet.2007.09.038
日期:2007.11
The reaction of 1,3-dicarbonyl compounds such as acetoacetate, acetylacetone, dibenzoylmethane, and benzoylacetate with electron-deficient internal alkynes in the presence of catalytic amount of ReBr( CO) 5 in toluene under neutral conditions resulted in the formation of 4,5,6-trisubstituted 2H-pyran-2-ones in moderate to high yield. The reaction took place via a two-step sequence including the rhenium(I)-catalyzed addition of the activated methylenes to alkynes to give enolic 2-alkenyl derivatives, and subsequently dealcoholic cyclization to form 2H-pyran-2-one derivatives. (c) 2007 Elsevier Ltd. All rights reserved.
Copper oxide catalyzed domino process for the synthesis of substituted 2H-pyran-2-ones and polyhydroxy coumarin derivatives