Enantioselective N-Heterocyclic Carbene Catalyzed Synthesis of Functionalized Indenes
作者:Changhe Zhang、David W. Lupton
DOI:10.1021/acs.orglett.7b01981
日期:2017.9.1
An enantioselective NHC (N-heterocycliccarbene) catalyzed synthesis of indenes from bifunctional α,β-unsaturated acyl fluorides and TMS enol ethers has been discovered. The reaction has broad generality (31 examples) and proceeds with high levels of enantioselectivity (most >92:8 er). Mechanistically the reaction likely occurs via a Michael/β-lactonization/decarboxylation sequence. Derivatization
A nickel‐catalyzed alkylation of polycyclic aromatic methyl ethers as well as methyl enol ethers with B‐alkyl 9‐BBN and trialkylborane reagents that involves the cleavage of stable C(sp2)−OMe bonds is described. The transformation has a wide substrate scope and good chemoselectivity profile while proceeding under mild reaction conditions; it provides a versatile way to form C(sp2)−C(sp3) bonds that
Visible Light-Induced Methoxycarbonyldifluoromethylation of Trimethylsilyl Enol Ethers and Allyltrimethylsilanes with FSO<sub>2</sub>
CF<sub>2</sub>
CO<sub>2</sub>
Me
作者:Wei Yu、Yao Ouyang、Xiu-Hua Xu、Feng-Ling Qing
DOI:10.1002/cjoc.201800318
日期:2018.11
omethylation of trimethylsilyl enol ethers with FSO2CF2CO2Me in the presence of fac‐Ir(ppy)3 was developed. This reaction provided a practical strategy for the construction of various α‐CF2CO2R aromatic ketones, which are difficult to access by other methods. Furthermore, a series of methoxycarbonyldifluoromethylated allylic compounds could also be obtained from allyltrimethylsilanes using the same
在fac -Ir(ppy)3存在下,用FSO 2 CF 2 CO 2 Me对三甲基甲硅烷基烯醇醚进行了光催化甲氧基羰基二氟甲基化反应。该反应的各种α-CF的构造提供了一种实用的策略2 CO 2 - [R芳族酮,这是难以通过其它方法获得。此外,也可以使用相同策略从烯丙基三甲基硅烷获得一系列甲氧基羰基二氟甲基化的烯丙基化合物。所得的含CF 2 CO 2 R的产品是有用的组成部分,在药物化学和材料科学中具有潜在的价值。
Ru
<sup>V</sup>
‐Acylimido Intermediate in [Ru
<sup>IV</sup>
(Por)Cl
<sub>2</sub>
]‐Catalyzed C–N Bond Formation: Spectroscopic Characterization, Reactivity, and Catalytic Reactions
作者:Dan‐Yan Hong、Yungen Liu、Liangliang Wu、Vanessa Kar‐Yan Lo、Patrick H. Toy、Siu‐Man Law、Jie‐Sheng Huang、Chi‐Ming Che
DOI:10.1002/anie.202100668
日期:2021.8.16
bond formationreactions via acylnitrene transfer have recently attracted much attention, but direct detection of the proposed acylnitrenoid/acylimido M(NCOR) (R=aryl or alkyl) species in these reactions poses a formidable challenge. Herein, we report on Ru(NCOR) intermediates in C−N bond formation catalyzed by [RuIV(Por)Cl2]/N3COR, a catalytic method applicable to aziridine/oxazoline formation from
The asymmetric radical-initiated difunctionalization of internal alkenes, which creates two vicinal stereocenters, has been a significant synthetic challenge despite the tremendous progress achieved for terminal alkenes. This is attributable to the common stepwise mechanism that involves an initial free radical addition to the alkene in a nonstereoselective fashion. We report here the first asymmetric
尽管末端烯烃取得了巨大进展,但内部烯烃的不对称自由基引发的双官能化(产生两个邻位立体中心)一直是一项重大的合成挑战。这归因于通常的逐步机理,该机理涉及以非立体选择性方式将初始自由基加成至烯烃。在铜(I)-金鸡纳生物碱基磺酰胺催化剂存在下,我们在这里报告了β,γ-不饱和酮肟中末端和内部芳基烯烃的第一个不对称自由基1,2-氧磺酰化。实验和计算机制研究共同支持Cu II -Cu I这种机制的特点是将磺酰基快速,可逆地加成到烯烃上,并随后由速率和立体决定C-O键的形成,即在Curtin-Hammett动力学控制下的情况。该方法为各种有价值的手性含磺酰基的结构单元的各种阵列的集体合成提供了鲁棒的平台。