Catalyst‐Free Deaminative Functionalizations of Primary Amines by Photoinduced Single‐Electron Transfer
作者:Jingjing Wu、Phillip S. Grant、Xiabing Li、Adam Noble、Varinder K. Aggarwal
DOI:10.1002/anie.201814452
日期:2019.4.16
The use of pyridinium‐activated primary amines as photoactive functional groups for deaminative generation of alkyl radicals under catalyst‐free conditions is described. By taking advantage of the visible light absorptivity of electron donor–acceptor complexes between Katritzky pyridiniumsalts and either Hantzsch ester or Et3N, photoinduced single‐electron transfer could be initiated in the absence
Formal Regiocontrolled Hydroboration of Unbiased Internal Alkynes via Borylation/Allylic Alkylation of Terminal Alkynes
作者:Abraham L. Moure、Pablo Mauleón、Ramón Gómez Arrayás、Juan Carlos Carretero
DOI:10.1021/ol4007663
日期:2013.4.19
boronates from terminalalkynes, a propargyl directing (2-pyridyl)sulfonyl group allows terminalalkynes to undergo Cu-catalyzed B2(pin)2-borylation and subsequent Cu-catalyzed allylic alkylation with Grignard reagents without affecting the pinacolboronate moiety, thereby formally enabling a highly stereo- and regiocontrolled access to hydroboration products of unbiased dialkyl internal alkynes.
The electrochemical borylation of electron-deficient alkenes and allenoates is described. In an undivided cell under galvanostatic conditions, a panel of Michael acceptors and allenoates was readily reacted. The reaction was efficient and the products were obtained in good to excellent yields (20 examples, 47 % to 91 % yield), offering an access to versatile borylated building blocks.
Suzuki–Miyaura Coupling Reactions of Conjunctive Reagents: 2-Borylated Allylic Sulfones
作者:Erich F. Altenhofer、Michael Harmata
DOI:10.1021/acs.joc.5b01253
日期:2015.8.21
In support of various efforts in our group, we developed methods for the convenient Suzuki-Miyaura coupling of borylated allylic sulfones with various electrophiles in both inter- and the less common intramolecular modes. The procedure facilitates the preparation of a wide variety of sulfones in a straightforward fashion, including six- through eight-membered rings.
Synthesis of Functionalized Cyclic Boronates
作者:Erich Altenhofer、Michael Harmata
DOI:10.1021/ol4029918
日期:2014.1.3
Deprotonation of a simple borylated allylic sulfone and subsequent alkylation with certain unsaturated electrophiles provide substrates that are easily converted into functionalized alkenyl boronates with ring sizes from five- to seven-membered. A Chan-Lam reaction on one such substrate afforded an alkoxyallylic sulfone that was readily converted via a (4 + 3)-cycloaddition to a polycycle possessing the ABC ring substructure of ingenol.