已经提出了一种直接闭环策略,该策略涉及用于合成苯并 [ b ] 氮卓类化合物的o -炔基苯胺衍生物的不太容易进行 7-内切-挖掘碳环化。由于氮的高亲核性,在 o -炔基苯胺衍生物中的微不足道的 5-内切环化已被克服,通过在金催化下使用它们的插烯酰胺来获得广泛的苯并[ b ]]azepines 以原子经济的方式具有出色的官能团相容性。氘加扰实验和 DFT 研究支持一种机制,该机制涉及通过关键的环丙基金卡宾中间体稳定最初形成的七元乙烯基金中间体的构象变化及其随后由抗衡阴离子介导的原脱氧反应。
Ruthenium-catalyzedpropargylicreduction of propargylicalcohols bearing a terminal alkyne moiety is accomplished by using Hantzsch ester as a nucleophilic hydride source. A variety of secondary and tertiary propargylicalcohols are reduced to the corresponding propargylic reduced products such as 1-alkynes in excellent yields. Some mechanistic studies indicate that ruthenium–allenylidene complexes
In order to get further information on the effect of terminal groups on the spectral regularity of diarylpoly-ynes, we carried out the syntheses of bis(4-biphenylyl)poly-ynes (In, n=1–6) and 2,2′-difluorenylpoly-ynes (IIn, n=1–4 and 6). The bathochromic shift of the longest-wavelength absorption maxima (λL) along with the increase in n was found to be expressed by the following empirical formulas:In:λL=24
It has been shown that some chalcones are able to inhibit tubulin polymerization, giving cytotoxicity and destruction
of tumoral vasculature. A library of 180 novel chalcone analogs has been synthesized via click chemistry and
screened for their cytotoxicity and tubulin assembly inhibition. 10 out 180 click chalcones displayed low micromolar cytotoxicity
but only compound Nf depicted antitubulin activity. While Nf displayed only micromolar potency this result
shows click-chalcones may be anti-tubulin agents and validate this strategy to search for novel active chemical entities.
Allenylic Carbonates in Enantioselective Iridium-Catalyzed Alkylations
作者:David A. Petrone、Mayuko Isomura、Ivan Franzoni、Simon L. Rössler、Erick M. Carreira
DOI:10.1021/jacs.8b01416
日期:2018.4.4
products obtained was highlighted in a variety of stereoselective transition metal-catalyzed difunctionalization reactions. Furthermore, a combination of experimental and theoretical studies provide support for a putative reactionmechanism wherein enantiodetermining C-C coupling occurs via nucleophilic attack on a highly planarized aryl butadienylium π-system that is coordinated to the Ir center in an η2-fashion
Gold‐Catalyzed Dehydrogenative Cycloisomerization of 1,4‐Enyne Esters to 3,5‐Disubstituted Phenol Derivatives
作者:Cuili Chen、Xianxiao Chen、Xiaoxiang Zhang、Shifa Wang、Weidong Rao、Philip Wai Hong Chan
DOI:10.1002/adsc.201701068
日期:2017.12.19
dehydrogenative cycloisomerization of 1,4‐enyne esters in the presence of 2,3‐dichloro‐5,6‐dicyanobenzoquinone (DDQ) or N‐fluorobenzenesulfonimide (NFSI) is described. The synthetic versatility of the methodology was exemplified by a gram‐scale reaction of one example, the ease to realize subsequent functional transformations of an adduct, and the application of the method to the synthesis of the bioactive