Deoxygenative Borylation of Secondary and Tertiary Alcohols
作者:Florian W. Friese、Armido Studer
DOI:10.1002/anie.201904028
日期:2019.7.8
Two different approaches for the deoxygenative radical borylation of secondary and tertiary alcohols are presented. These transformations either proceed through a metal‐free silyl‐radical‐mediated pathway or utilize visible‐light photoredox catalysis. Readily available xanthates or methyl oxalates are used as radical precursors. The reactions show broad substrate scope and high functional‐group tolerance
α-C–H borylation of secondary alcohols <i>via</i> Ru/Fe relay catalysis: building a platform for alcoholic C–H/C–O functionalizations
作者:Qing Zhu、Zeyu He、Lu Wang、Yue Hu、Chungu Xia、Chao Liu
DOI:10.1039/c9cc06135e
日期:——
unprecedented α-C–H borylation of secondary alcohols was successfully achieved and delivered various tertiary α-boryl alcohols via [Ru]/[Fe] relay catalysis. The dehydrogenation catalyst (Ru) and borylation catalyst (Fe) interacted to increase the chemoselectivity. By installing the “platform functional group” Bpin via this α-C–H borylation, several alcoholic α-C–H and C–O bond functionalizations were
Synthesis of Secondary and Tertiary Alkyl Boronic Esters by <i>gem</i>
-Carboborylation: Carbonyl Compounds as Bis(electrophile) Equivalents
作者:Dunfa Shi、Lu Wang、Chungu Xia、Chao Liu
DOI:10.1002/anie.201804684
日期:2018.8.6
tertiary alkyl boronic esters. The addition of B2pin2 to a carbonyl compound generates α‐oxyl‐substituted alkyl boron species. Organolithium and Grignard reagents are then applied as C nucleophiles for the 1,2‐metalate rearrangement process. The organolithium reagents can also be generated by C−H lithiation or halogen/lithium exchange. The use of chiral ligands led to the generation of chiral alkyl boronic
Metal catalyst-free photo-induced alkyl C–O bond borylation
作者:Guobin Ma、Changzhou Chen、Sangita Talukdar、Xinluo Zhao、Chuanhu Lei、Hegui Gong
DOI:10.1039/d0cc04776g
日期:——
Metal catalyst free, blue visible light-induced C–O bond borylation of unactivated tertiary alkyl methyl oxalates has been developed to furnish tertiary alkyl boronates. From the secondary alcohols activated with imidazolylthionyl, moderate yields of boronates were attained under standard photo-induced conditions. Preliminary mechanisticstudies confirmed the involvement of a (DMF)2–B2cat2 adduct that
Synthesis of Secondary and Tertiary Alkylboranes via Formal Hydroboration of Terminal and 1,1-Disubstituted Alkenes
作者:Hilary A. Kerchner、John Montgomery
DOI:10.1021/acs.orglett.6b03090
日期:2016.11.4
terminal or 1,1-disubstituted alkenes with bis(pinacolato)diboron and methanol provides formal hydroboration products with exceptional regiocontrol favoring the branched isomer. Pairing this procedure with photocatalytic cross-couplings using iridium and nickel cocatalysis provides an effective, highlyregioselective procedure for the hydroarylation of terminal alkenes.