Oxidative γ-Addition of Enals to Trifluoromethyl Ketones: Enantioselectivity Control via Lewis Acid/N-Heterocyclic Carbene Cooperative Catalysis
作者:Junming Mo、Xingkuan Chen、Yonggui Robin Chi
DOI:10.1021/ja303618z
日期:2012.5.30
An oxidative γ-functionalization of enals under N-heterocyclic carbene (NHC) catalysis to give unsaturated δ-lactones is disclosed. Enantioselectivity control involving the relatively remote enal γ-carbon was achieved via Lewis acid [Sc(OTf)(3) or combined Sc(OTf)(3)/Mg(OTf)(2)] and NHC cooperativecatalysis.
Green and Rapid Access to Benzocoumarins<i>via</i>Direct Benzene Construction through Base-Mediated Formal [4+2] Reaction and Air Oxidation
作者:Chengli Mou、Tingshun Zhu、Pengcheng Zheng、Song Yang、Bao-An Song、Yonggui Robin Chi
DOI:10.1002/adsc.201500771
日期:2016.3.3
typically with an intramolecular ester forming reaction to make the lactone ring as the last step. Another major method involves transition metal‐catalyzed coupling or carbon‐hydrogen bond activation reactions starting with pre‐existing aryl frameworks in the substrates. Here we report a new strategy for the green and rapidaccess to benzocoumarins and their derivatives. Our method uses readily available
Base-catalysed reductive relay hydroboration of allylic alcohols with pinacolborane to form alkylboronic esters
作者:Zi-Chao Wang、Di Shen、Jian Gao、Xian Jia、Youjun Xu、Shi-Liang Shi
DOI:10.1039/c9cc03459e
日期:——
An unprecedented base-catalysed reductive relay hydroboration of allylicalcohols is described. Commercially available nBuLi was found to be a robust transition metal-free initiator for this protocol, affording various boronic esters in high yield and selectivity. Mechanistically, this methodology involves a one-pot three-step successive process (dehydrocoupling/allylic hydride substitution/anti-Markovnikov
作者:Priyanka Chakraborty、Subhankar Pradhan、J. Richard Premkumar、Basker Sundararaju
DOI:10.1016/j.jcat.2023.03.031
日期:2023.5
earth-abundant low-valent iron complex. The scope of the reaction is extremely broad, and numerous terpenols, including geraniol, nerol, prenol, farnesol, geranylgeraniol, phytol, and solanesol, can be utilized. Furthermore, the developed method can also extend to non-natural synthetic terpenols. A plausible catalytic cycle is proposed based on a series of in-depth mechanistic studies, kinetic experiments, and
直接从生物质衍生的氧化碳氢化合物与利用氢自动转移的亲碳核试剂形成C C 键很有趣,因为它不会产生废物。我们展示了使用从天然来源(例如精油)中提取的氧化萜烯,使用明确定义的地球丰富的低价铁络合物对羟吲哚进行直接烷基化。反应范围非常广泛,可以使用多种萜烯醇,包括香叶醇、橙花醇、异戊烯醇、法尼醇、香叶基香叶醇、叶绿醇和茄尼醇。此外,所开发的方法还可以扩展到非天然合成萜烯醇。基于一系列深入的机理研究、动力学实验和 DFT 分析,提出了一个合理的催化循环。
Construction of polycyclic compounds by cyclocarbonylation. 6. Palladium-catalyzed cyclocarbonylation of 3-(heteroaryl)allyl acetates
Acetoxybenzofurans, acetoxybenzothiophenes, acetoxyindoles, and acetoxycarbazoles were obtained in high yields by cyclocarbonylation of 3-furyl-, 3-thienyl-, 3-pyrrolyl-, and 3-indolylallyl acetates, respectively, in the presence of Ac2O, NEt3, and a catalytic amount of PdCl2(PPh3)2 at 130-170-degrees-C under 50-70 atm of CO. 3-(3-Furyl)allyl and 3-(3-thienyl)allyl acetates cyclized selectively at the 2-position of the heterocyclic nucleus to give 7-acetoxybenzofuran and 7-acetoxybenzothiophene, respectively. The synthetic utility of the reaction was demonstrated by the synthesis of cannabifuran from isothymol.