Selective Oxidation of Benzylic and Allylic Alcohols Using Mn(OAc)<sub>3</sub>/Catalytic 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone
作者:Casey C. Cosner、Pablo J. Cabrera、Katherine M. Byrd、Asia M. Adams Thomas、Paul Helquist
DOI:10.1021/ol200441g
日期:2011.4.15
A practical, chemoselectiveoxidation of alcohols employing catalytic quantities of DDQ as the oxidant and Mn(OAc)3 as the co-oxidant is described. Electron-rich benzylicalcohols are oxidized efficiently to their corresponding carbonyls, but less electron-rich benzylicalcohols remain unchanged. Allylicalcohols are rapidly oxidized to their corresponding aldehyde or ketone counterparts in high yields
Iridium-catalyzed direct asymmetric vinylogous allylic alkylation
作者:Chang-Yun Shi、Jun-Zhao Xiao、Liang Yin
DOI:10.1039/c8cc07249c
日期:——
alkylation of α,β-unsaturated lactones (including coumarins) was achieved with excellent regio- and enantioselectivity. Transformations of the product were carried out by means of the versatile terminal olefin and lactonemoieties. The synthetic application of the present methodology was showcased by the asymmetric synthesis of an advanced synthetic Merck intermediate toward a new drug candidate.
Straightforward chemo- and stereoselective fluorocyclopropanation of allylic alcohols: exploiting the electrophilic nature of the not so elusive fluoroiodomethyllithium
作者:Marco Colella、Arianna Tota、Angela Großjohann、Claudia Carlucci、Andrea Aramini、Nadeem S. Sheikh、Leonardo Degennaro、Renzo Luisi
DOI:10.1039/c9cc03394g
日期:——
fluorocyclopropanation of allylicalcohols is reported. This simple method involves the not so elusive fluoroiodomethyllithium, a carbenoidic intermediate that under the developed conditions discloses its electrophilic nature. Gratifyingly, the reaction turned out to be highly chemo- and stereoselective, and DFT calculations provided insights into the structure and nature of this new type of carbenoid.
Donor‐Acceptor Cyclopropanes: Activation Enabled by a Single, Vinylogous Acceptor
作者:Nils L. Ahlburg、Oliver Hergert、Peter G. Jones、Daniel B. Werz
DOI:10.1002/anie.202214390
日期:2023.1.2
A new class of donor-acceptor cyclopropanes bearing only a single, vinylogousacceptor moiety is presented. The system is capable of cycloadditions through Brønsted or Lewis acid catalysis with numerous reagents: aldehydes, ketones, thioketones, nitriles, naphth-2-ols, cyclopropanes, nitrones and isobenzofurans. The mechanism was explored in detail by kinetic and mechanistic experiments.