Ring-Opening Reactions of Donor–Acceptor Cyclobutanes with Electron-Rich Arenes, Thiols, and Selenols
作者:Alexander Kreft、Stephanie Ehlers、Peter G. Jones、Daniel B. Werz
DOI:10.1021/acs.orglett.9b02197
日期:2019.8.16
Donor–acceptor (D–A) cyclobutanes with two geminal ester groups as acceptors are reacted with electron-rich arenes as nucleophiles to afford ring-opened products. AlCl3 mediates this Friedel–Crafts-type reaction. A variety of donors and electron-rich arenes are used. Nucleophilic thiols and selenols also trigger this ring-opening reaction. Furthermore, a comparison of various physical parameters has
Friedel–Crafts-Type Reactions with Electrochemically Generated Electrophiles from Donor–Acceptor Cyclopropanes and -Butanes
作者:Simon Kolb、Nils L. Ahlburg、Daniel B. Werz
DOI:10.1021/acs.orglett.1c01890
日期:2021.7.16
describe a general electrochemical method to functionalize donor–acceptor (D–A) cyclopropanes and -butanes with arenes utilizing Friedel–Crafts-type reactivity. The catalyst-free strategy relies on the direct anodic oxidation of the strained carbocycles, which leads after C(sp3)–C(sp3) cleavage to radical cations that act as electrophiles for the arylation reaction. Broad reaction scopes in regard to
Cycloadditions of Donor–Acceptor Cyclopropanes and ‐butanes using S=N‐Containing Reagents: Access to Cyclic Sulfinamides, Sulfonamides, and Sulfinamidines
作者:Gwyndaf A. Oliver、Maximilian N. Loch、André U. Augustin、Pit Steinbach、Mohammed Sharique、Uttam K. Tambar、Peter G. Jones、Christoph Bannwarth、Daniel B. Werz
DOI:10.1002/anie.202106596
日期:2021.12
By employing (3+2)- and (4+2)-cycloadditions of donor–acceptor (D–A) cyclopropanes and cyclobutanes with N-sulfinylamines and sulfur diimides, a variety of isothiazolidines and thiazinanes were synthesized. Use of a sulfinylamine bearing a leaving group, followed by oxidation, led to formal insertion of HNSO2 providing γ-sultams with no N-substitution.
Synthesis of 2-Unsubstituted Pyrrolidines and Piperidines from Donor–Acceptor Cyclopropanes and Cyclobutanes: 1,3,5-Triazinanes as Surrogates for Formylimines
作者:Lennart K. B. Garve、Alexander Kreft、Peter G. Jones、Daniel B. Werz
DOI:10.1021/acs.joc.7b01631
日期:2017.9.1
A synthetic procedure to access 2-unsubstituted pyrrolidines and piperidines is presented. In the presence of MgI2 as Lewis acid, donor–acceptor cyclopropanes or corresponding cyclobutanes were treated with 1,3,5-triazinanes, leading to the five- or six-membered ring systems under mild conditions in yields up to 93%. This protocol tolerates a great variety of functional groups and thus provides an
Synthesis of Functionalized Tetrahydropyridines by SnCl
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‐Mediated [4+2] Cycloaddition between Donor–Acceptor Cyclobutanes and Nitriles
作者:David Tong、Jackie Wu、Nathan Bazinski、Donghyun Koo、Naresh Vemula、Brian L. Pagenkopf
DOI:10.1002/chem.201903833
日期:2019.12.2
Cycloadditions of strained carbocycles promoted by Lewis acids are powerful methods to construct heterocyclic frameworks. In fact, the formal [3+2] cycloadditions of donor-acceptor (DA) cyclopropanes with nitriles has seen particular success in synthesis. In this work, we report on the first [4+2] cycloaddition of nitriles with DA cyclobutanes by Lewis acid activation. Tetrahydropyridine derivatives