Ring Opening of Donor-Acceptor Cyclopropanes with the Azide Ion: A Tool for Construction of N-Heterocycles
作者:Konstantin L. Ivanov、Elena V. Villemson、Ekaterina M. Budynina、Olga A. Ivanova、Igor V. Trushkov、Mikhail Ya. Melnikov
DOI:10.1002/chem.201405551
日期:2015.3.23
general method for ringopening of various donor–acceptor cyclopropanes with the azide ion through an SN2‐like reaction has been developed. This highly regioselective and stereospecific process proceeds through nucleophilic attack on the more‐substituted C2 atom of a cyclopropane with complete inversion of configuration at this center. Results of DFT calculations support the SN2 mechanism and demonstrate
已经开发出一种通用的方法,可通过类似S N 2的反应,将叠氮离子与各种供体-受体环丙烷开环。这种高度区域选择性和立体选择性的过程是通过亲核攻击环丙烷的更取代的C2原子进行的,该中心的构型完全反转。DFT计算结果支持S N2机理,证明环丙烷的相对实验反应性与计算出的能垒之间具有良好的定性相关性。该反应为多种多官能叠氮化物提供了一种简单的方法,产率高达91%。这些叠氮化物具有很高的合成效用,并参与了面向多样性的合成,这是通过已开发的将其转变为五元,六元和七元N杂环以及复杂的环状化合物的多径策略证明的。包括天然产物和药物,如(-)-尼古丁和阿托伐他汀。
Diastereo- and Enantioselective Synthesis of α,β-Disubstituted γ-Bisalkoxycarbonyl Sulfonates
The asymmetric synthesis of α,β-disubstituted γ-bisalkoxycarbonyl sulfonates is reported. The synthesis is based on the Michael addition of a lithiated enantiopure sulfonate bearing a cheap chiral sugar auxiliary to Knoevenagel acceptors. The reaction proceeds with high asymmetric inductions (ds = 69-96%) and good yields (62-79%). The absolute configuration was determined by X-ray crystal-structure analysis.
Regioselective Hydrogenolysis of Donor–Acceptor Cyclopropanes with Zn-AcOH Reductive System
作者:Konstantin L. Ivanov、Elena V. Villemson、Gennadij V. Latyshev、Stanislav I. Bezzubov、Alexander G. Majouga、Mikhail Ya. Melnikov、Ekaterina M. Budynina
DOI:10.1021/acs.joc.7b01549
日期:2017.9.15
convenient low-cost method for regioselective ring-opening of donor–acceptor cyclopropanes with the Zn-AcOH reductive system was developed. The general character of the method was displayed via efficient reduction of a representative series of 2-(het)arylcyclopropane-1,1-diesters as well as donor–acceptor cyclopropanes with other types of electron-withdrawing activating groups. This method opens a rapid
Organocatalyzed enantioselective Michael addition/cyclization cascade reaction of 3-isothiocyanato oxindoles with arylidene malonates
作者:Raghunath Chowdhury、Mukesh Kumar、Sunil K. Ghosh
DOI:10.1039/c6ob02104b
日期:——
An organocatalyzed Michael addition–cyclization reaction between 3-isothiocyanatooxindoles and arylidene malonates has been developed for the synthesis of highly functionalized 3,2′-pyrrolidinyl spirooxindole derivatives. The reaction was catalyzed by a quinine derived tertiary amino-thiourea based bifunctional catalyst or its pseudo-enantiomeric quinidine derived catalyst providing both the enantiomers
Acetal Addition to Electron-Deficient Alkenes with Hydrogen Atom Transfer as a Radical Chain Propagation Step
作者:Wei Chuen Chan、Jincy K. Vinod、Kazunori Koide
DOI:10.1021/acs.joc.0c03044
日期:2021.2.19
We describe a visible-light-promoted addition of a hydrogen atom and an acetal carbon toward various electron-deficientalkenes. 1,3-Dioxolane is converted to its radical species in the presence of persulfate and an iridium catalyst upon visible light irradiation, which then reacts with electron-deficientalkenes. The reaction operates via a radical chain mechanism, a less commonly observed pathway