Nickel-Catalyzed Arylboration of Alkenylarenes: Synthesis of Boron-Substituted Quaternary Carbons and Regiodivergent Reactions
作者:Liang-An Chen、Alan R. Lear、Pin Gao、M. Kevin Brown
DOI:10.1002/anie.201904861
日期:2019.8.5
A method for the construction of boron‐substituted quaternary carbons or diarylquaternary carbons by arylboration of highly substituted alkenylarenes is presented. A wide range of alkenes and arylbromides can participate in this reaction thus allowing for a diverse assortment of products to be prepared. In addition, a solvent dependent regiodivergent arylboration of 1,2‐disubstituted alkenylarenes
Catalytic Ring Expansion of Vinyl Oxetanes: Asymmetric Synthesis of Dihydropyrans Using Chiral Counterion Catalysis
作者:Boying Guo、Gregg Schwarzwalder、Jon T. Njardarson
DOI:10.1002/anie.201201367
日期:2012.6.4
Acid Showdown! The first catalyticring expansion of vinyl oxetanes to 3,6‐dihydro‐2H‐pyrans is described. Copper(II) triflate emerged as the best catalyst for this new transformation, which has broad scope as demonstrated by the eighteen examples included. The symmetric vinyl oxetane substrate can be asymmetrically desymmetrized when using either chiral Lewis or Brønsted acids as catalysts.
Three‐Component Difunctionalization of Cyclohexenyl Triflates: Direct Access to Versatile Cyclohexenes via Cyclohexynes
作者:Seoyoung Cho、E. J. McLaren、Qiu Wang
DOI:10.1002/anie.202109482
日期:2021.12.6
dicarbofunctionalization, aminohalogenation and aminocarbonation of readily available cyclohexenyl triflates, via strained cyclic alkyne intermediates generated in situ. The importance and utility of this method is exemplified by the modularity of this approach and the ease in which even highly complex polycyclic scaffolds can be accessed in one step.
Catalytic Friedel‐Crafts Reactions on Saturated Heterocycles and Small Rings for sp
<sup>3</sup>
‐sp
<sup>2</sup>
Coupling of Medicinally Relevant Fragments
作者:Rosemary A. Croft、Maryne A. J. Dubois、Alexander J. Boddy、Camille Denis、Anna Lazaridou、Anne Sophie Voisin‐Chiret、Ronan Bureau、Chulho Choi、James J. Mousseau、James A. Bull
DOI:10.1002/ejoc.201900498
日期:2019.9
A systematic comparison of Lewis acid catalysts [Ca(II), Li(I) and Fe(III)] is presented for catalytic Friedel–Crafts reactions using alcohols on 4‐, 5‐, and 6‐membered oxygen and nitrogen heterocycles and cyclobutanes, forming gem‐diaryl quaternary centers.
Electro‐Olefination—A Catalyst Free Stereoconvergent Strategy for the Functionalization of Alkenes
作者:Andreas N. Baumann、Arif Music、Jonas Dechent、Nicolas Müller、Thomas C. Jagau、Dorian Didier
DOI:10.1002/chem.202001394
日期:2020.7.8
Conventional methods carrying out C(sp2)−C(sp2) bondformations are typically mediated by transition‐metal‐based catalysts. Herein, we conceptualize a complementary avenue to access such bonds by exploiting the potential of electrochemistry in combination with organoboron chemistry. We demonstrate a transition metal catalyst‐free electrocoupling between (hetero)aryls and alkenes through readily available