Reductive Arylation of Arylidene Malonates Using Photoredox Catalysis
作者:Rick C. Betori、Karl A. Scheidt
DOI:10.1021/acscatal.9b03608
日期:2019.11.1
the utilization of these operators in intermolecular radical–radical arylations, while avoiding conjugate addition/dimerization reactivity that is commonly encountered in enone-based photoredox chemistry. This reactivity relies on tertiary amines that serve to both activate the arylidene malonate for single-electron reduction by a proton-coupledelectrontransfer mechanism as well as serve as a terminal
BF
<sub>3</sub>
Mediated [1,5]‐Hydride Shift Triggered Cyclization: Thioethers Join the Game
作者:Elvira R. Zaitseva、Alexander Yu. Smirnov、Vladimir I. Timashev、Vadim I. Malyshev、Ekaterina A. Zhigileva、Andrey A. Mikhaylov、Michael G. Medvedev、Nadezhda S. Baleeva、Mikhail S. Baranov
DOI:10.1002/ejoc.202200547
日期:2022.7.7
1,5-Hydride shift triggered the cyclization of 2-(2-(benzylthio)benzylidene)malonates to thiachromanes, which are presented for the first time. Boron trifluoride as a reaction promotor is the key of this C−H activation success. Quantum chemical calculations have shown that the studied reaction proceeds via a O–BF2–O chelate, which was confirmed by NMR-analysis.
C−H Bond Functionalization via Hydride Transfer: Synthesis of Dihydrobenzopyrans from <i>ortho</i>-Vinylaryl Akyl Ethers
作者:Kevin M. McQuaid、Jonathan Z. Long、Dalibor Sames
DOI:10.1021/ol900915p
日期:2009.7.16
The hydride transfer initiated cyclization ("HT-cyclization") of aryl alkyl ethers, which leads to direct coupling of sp(3) C-H bonds and activated alkenes, is reported. Readily available salicylaldehyde derived ethers are converted in one step to dihydrobenzopyrans, an important class of heteroarenes frequently found in biologically active compounds. This process has not been previously reported, in contrast to known HT-cyclizations of the corresponding tert-amines ("tert-amino effect" reactions).
Expeditious Synthesis of Benzopyrans via Lewis Acid-Catalyzed C−H Functionalization: Remarkable Enhancement of Reactivity by an <i>Ortho</i> Substituent
An expeditious construction of a benzopyran skeleton via Lewis acid-catalyzed C−H functionalization was achieved. In this process, a [1,5] hydride shift and 6-endo cyclization successively occurred to give benzopyrans. The presence of substituents ortho to the alkoxygroup significantly enhanced the reactivity, affording the desired compounds in excellent chemical yields with short reaction times.