Phosphazenomalonates as Catalysts and Reactants in (4+3) Annulation to Acrolein
摘要:
The concept of combining a catalyst and an activated center in one molecule was implemented in Michael donors functionalized with phosphazene units. First, the phosphazene group catalyzes Michael addition and then acts as a reactant in an intramolecular aza-Wittig reaction. The viability of this strategy was demonstrated by our development of a one-pot method for azepane core construction starting from functionalized azides, triphenylphosphine and acrolein.
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。
Duality of Donor-Acceptor Cyclopropane Reactivity as a Three-Carbon Component in Five-Membered Ring Construction: [3+2] Annulation Versus [3+2] Cycloaddition
作者:Yulia A. Volkova、Ekaterina M. Budynina、Alexey E. Kaplun、Olga A. Ivanova、Alexey O. Chagarovskiy、Dmitriy A. Skvortsov、Victor B. Rybakov、Igor V. Trushkov、Mikhail Ya. Melnikov
DOI:10.1002/chem.201300731
日期:2013.5.17
Quo vadis? The Lewis acid catalyzed reaction of (hetero)aryl‐derived donor–acceptorcyclopropanes with alkenes can be selectively directed along a [3+2] annulation pathway (see scheme). This new process provides convenient and efficient access to indanes and other cyclopentannulated (hetero)arenes, among which polyoxygenated 1‐arylindanes exhibit significant cytotoxicity against several cancer cell
Ring opening of DA-cyclopropanes with electron rich arene/heteroarene: synthesis of 2-(2,2-diarylethyl)malonates
作者:Ranadeep Talukdar、Amrita Saha、Deo Prakash Tiwari、Manas K. Ghorai
DOI:10.1016/j.tet.2015.12.001
日期:2016.2
strategy for nucleophilic ring opening of donor-acceptor (DA)-cyclopropanes with electronrich arenes to provide 2-(2,2-diarylethyl)malonates in excellent yields is described. The reaction was found to be successful with heteroarenes as the nucleophile as well. Reaction of enantiopure DA-cyclopropane with arene/heteroarene as the nucleophiles afforded the corresponding 2-(2,2-diarylethyl)malonates with
Diastereoselective Synthesis of Functionalized Tetrahydrocarbazoles via a Domino-Ring Opening–Cyclization of Donor–Acceptor Cyclopropanes with Substituted 2-Vinylindoles
作者:Ranadeep Talukdar、Deo Prakash Tiwari、Amrita Saha、Manas K. Ghorai
DOI:10.1021/ol501763n
日期:2014.8.1
synthetic approach for the synthesis of highly functionalized tetrahydrocarbazoles via DROC of various functionalized DA-cyclopropanes with 2-indolylnitroethylene and indole-substituted alkylidene malonate is described. The tetrahydrocarbazoles were obtained with excellent diastereoselectivity having cis alignment of the 1,4-appendages across the six-memberedcarbocyclic ring.
Stereospecific Syntheses of Enaminonitriles and β-Enaminoesters via Domino Ring-Opening Cyclization (DROC) of Activated Cyclopropanes with Pronucleophilic Malononitriles
作者:Amrita Saha、Aditya Bhattacharyya、Ranadeep Talukdar、Manas K. Ghorai
DOI:10.1021/acs.joc.7b03033
日期:2018.2.16
been developed via domino ring-opening cyclization (DROC) and DROC/decarboxylative tautomerization of activated cyclopropanes with malononitrile pronucleophiles, respectively. Both of the efficient strategies (yield up to 93%) have been generalized with various donor–acceptor and acceptor cyclopropanes as well as with malononitrile derivatives. The stereospecific variants of the two SN2-type DROC strategies