Enantioselective (3+2) cycloaddition <i>via</i> N-heterocyclic carbene-catalyzed addition of homoenolates to cyclic <i>N</i>-sulfonyl trifluoromethylated ketimines: synthesis of fused N-heterocycle γ-lactams
作者:Zhen-Zhen Zhang、Yongna Zhang、Hui-Xin Duan、Zhuo-Fei Deng、You-Qing Wang
DOI:10.1039/c9cc09269b
日期:——
An enantioselective (3+2) cycloaddition of enals and cyclic N-sulfonyl trifluoromethyl ketimines via N-heterocyclic carbene-catalyzed homoenolateaddition is described. This reaction can efficiently construct fused N-heterocycle γ-lactams bearing two adjacent chiral centers with >20 : 1 dr and 94-99% ee, with one chiral center as a trifluoromethylated α-tetrasubstituted carbon stereocenter.
Compounds and methods of preparing compounds represented by structural formula (I):
wherein X represents any suitable counter-anion;
R1 and R2 independently represent hydrogen, C1-6 alkoxy or nitro;
R3, R4, R5 and R6 each independently represents hydrogen, hydroxy, halo, C1-6 alkyl,
C2-6 alkenyl or C1-6 alkoxy; and
R7, R8, R9 and R10 each independently represents hydrogen, hydroxy, halo, C1-6 alkyl, C2-6 alkenyl or C1-6 alkoxy.
Compounds represented by structural formula (I) are useful in treating or preventing free radical-associated diseases or conditions in mammals.
Synthesis of Phenanthrene Derivatives by Intramolecular Cyclization Utilizing the [1,2]-Phospha-Brook Rearrangement Catalyzed by a Brønsted Base
作者:Azusa Kondoh、Takuma Aoki、Masahiro Terada
DOI:10.1002/chem.201501377
日期:2015.9.1
The synthesis of functionalized phenanthrene derivatives was achieved by intramolecular cyclization utilizing the [1,2]‐phospha‐Brook rearrangement under Brønsted base catalysis. Treatment of biaryl compounds having an α‐ketoester moiety and an alkyne moiety at the 2 and 2′ positions, respectively, with diisopropyl phosphite in the presence of a catalytic amount of phosphazene base P2‐tBu provides
功能化的菲衍生物的合成是通过在Brønsted碱催化下利用[1,2]-磷-布鲁克重排进行分子内环化来实现的。在催化量的磷腈碱P2 - t Bu存在下,用亚磷酸二异丙酯处理在2和2'位置分别具有α-酮酸酯部分和炔烃部分的联芳基化合物,可以得到9,10-二取代的菲衍生物。高产。该反应涉及通过乌珀隆过程生成酯烯酸酯,即将亚磷酸二异丙酯添加至酮部分,然后进行[1,2]-磷-布鲁克重排,将分子内添加至炔烃,以及[3] ,3]以连续方式重新排列烯丙基磷酸酯部分。
Substituent Effects in Chain-Breaking Aryltellurophenol Antioxidants
作者:Jia-fei Poon、Jiajie Yan、Kjell Jorner、Henrik Ottosson、Carsten Donau、Vijay P. Singh、Paul J. Gates、Lars Engman
DOI:10.1002/chem.201704811
日期:2018.3.7
more efficiently than α‐tocopherol, with three to five‐fold longer inhibition times. Thus, these compounds offer better and longer‐lasting antioxidant protection than recently prepared alkyltellurophenols. Compounds with electron‐donating para substituents in the aryltelluro or phenolic part of the molecule showed the best results. The mechanism for quenching peroxyl radicals was considered and discussed
Synthetic and computational studies on liphagal: a natural product inhibitor of PI-3K
作者:Yanzhong Zhang、E. Zachary Oblak、Erin S.D. Bolstad、Amy C. Anderson、Jerry P. Jasinski、Ray J. Butcher、Dennis L. Wright
DOI:10.1016/j.tetlet.2010.09.058
日期:2010.11
The natural product liphagal has been shown to function as a reasonably potent and selective inhibitor of the key signaling enzyme PI-3K alpha. We have been interested in developing an analog class of PI-3K inhibitors based upon this unusual terpenoid natural product. Toward that end, we have evaluated the binding of the natural product to its target protein computationally and formulated a class of simplified analogs based on the structural analysis. Utilizing the cycloadduct derived from tetrabromocyclopropene and furan, we were able to generate a key, versatile scaffold upon which to pursue this analog design. (C) 2010 Elsevier Ltd. All rights reserved.