The kinetics of the reactions of different heterocyclic anions derived from imidazoles, purines, pyrimidines, and related compounds with benzhydrylium ions and structurally related quinone methides have been studied in DMSO and water. The second‐order rate constants (log k2) correlated linearly with the electrophilicity parameters E of the electrophiles according to the correlation log k2 = sN(N+E)
Thiourea catalyzed 1,6-conjugate addition of indoles to para-quinone methides
作者:Guangmiao Wu、Tao Li、Fuhai Liu、Yulong Zhao、Shiqiang Ma、Shouchu Tang、Xingang Xie、Xuegong She
DOI:10.1016/j.tetlet.2021.153315
日期:2021.9
An efficient thiourea catalyzed 1,6-conjugate addition of indoles to -quinone methides (-QMs) was developed. -QMs was activated by a weak hydrogen-bond effect. The reaction is featured mild reaction conditions and wide substrate scope. A series of C-3 bisaryl methine substituted indoles are prepared in high yield.
The rates of the reactions of the colored para-substituted phenylacetonitrile anions 1a−c and the phenylpropionitrile anions 2a−c with Michael acceptors (3a−u) were determined by UV−vis spectroscopy in DMSO at 20 °C. The reactions follow second-order kinetics, and the corresponding rate constants k2 obey the linear-free-energy relationship log k2(20 °C) = s(N + E), from which the nucleophile-specific
1,6-Addition Arylation of para-Quinone Methides: An Approach to Unsymmetrical Triarylmethanes
作者:Shang Gao、Xiuyan Xu、Zhenbo Yuan、Haipin Zhou、Hequan Yao、Aijun Lin
DOI:10.1002/ejoc.201600385
日期:2016.6
A 1,6-addition arylation reaction of para-quinone methides with α-isocyanoacetamides and electron-rich aromatic compounds under metal-free conditions has been developed. BF3·Et2O plays two roles in the reaction: catalyzing the cyclization of α-isocyanoacetamides to give oxazoles, and activating the para-quinone methides to achieve the 1,6-addition arylation process. The reaction shows good functional
Iron catalyzed tandem ring opening/1,6-conjugate addition of cyclopropanols with <i>p</i>-quinone methides: new access to γ,γ-diaryl ketones
作者:Sachin R. Shirsath、Sagar M. Chandgude、M. Muthukrishnan
DOI:10.1039/d1cc05997a
日期:——
An iron(III) catalyzed tandem ring opening/1,6-conjugate addition of cyclopropanols to p-quinone methides leading to γ,γ-diaryl ketones has been described. This catalytic protocol provides a novel and efficient method to access γ,γ-diaryl ketone derivatives in good to excellent yields with high functional group tolerance. Importantly, γ,γ-diaryl ketone can be further functionalized to give a versatile