Phosphine-Catalyzed (3 + 2)/(3 + 2) Sequential Annulation of γ-Vinyl Allenoates: Access to Fused Carbocycles
作者:Jiaxu Feng、Yingying Chen、Wenhui Qin、You Huang
DOI:10.1021/acs.orglett.9b04176
日期:2020.1.17
The first (3 + 2)/(3 + 2) sequential annulation of γ-vinyl allenoates with alkylidenemalononitriles enabled by phosphine catalysis has been reported. A broad range of structurally dense tetra- and penta-substituted bicyclic[3,3,0]octene derivatives, containing a quaternary center and three sequential stereogenic center, were synthesized in good to excellent yields. In this approach, three new C-C bonds
Uses of ethyl benzoylacetate for the synthesis of thiophene, thiazole, pyridine, and pyran derivatives with antitumor activities
作者:Rafat M. Mohareb、Bahaa M. Mostafa
DOI:10.1002/jhet.3865
日期:2020.3
120°C gave the condensation product 3. The latter compound underwent a series of heterocyclization to give thiophene, thiazole, pyridine, and pyran derivatives. The structures of the synthesized products were established on the basis of analytical and spectral data. The antitumor evaluation of the newly synthesized products against the six cancer cell lines namely human gastric cancer (NUGC and HR), human
Base‐Catalyzed Synthesis of Spiropyrazoloaminonitriles with Arylidene Pyrazolone and Vinylogous Malononitriles through a Cascade Michael Addition and Cyclization
Synthesis of title compounds were accomplished by a reaction of vinyl malononitriles and arylidene pyrazolones catalyzed by base. This protocol proceeds via Michael addition followed by intramolecular cyclization leading to the formation of two new C−C bonds. Further the same reaction was also conducted with α,α-dicyano olefins and vinyl malononitriles to furnish 1,6-dihydro biphenyl compounds. Simple
Organocatalyzed Asymmetric 1,6-Conjugate Addition of <i>para</i>-Quinone Methides with Dicyanoolefins
作者:Xuanyi Li、Xiuyan Xu、Weiwei Wei、Aijun Lin、Hequan Yao
DOI:10.1021/acs.orglett.5b03471
日期:2016.2.5
A chiral thiourea catalyzed asymmetric 1,6-conjugate addition of para-quinone methides with dicyanoolefins has been developed. The reaction provided an efficient approach to the synthesis of chiral diarylmethine skeletons in good yields (up to 99% yield) with high diastereo- and enantioselectivity (>20:1 dr and up to 99.5:0.5 er), also on a gram scale. The preliminary mechanistic study showed that the remote stereocontrol was achieved through intermolecular hydrogen-bond interaction between the chiral thiourea catalyst and the para-quinone methides directly for the first time.