A highly useful, visible-light-driven carboxylation of aryl bromides and chlorides with CO2 was realized using a combination of Pd(OAc)2 as a carboxylation catalyst and Ir(ppy)2(dtbpy)(PF6) as a photoredox catalyst. This carboxylation reaction proceeded in high yields under 1 atm of CO2 with a variety of functionalized aryl bromides and chlorides without the necessity of using stoichiometric metallic
使用 Pd(OAc)2 作为羧化催化剂和 Ir(ppy)2(dtbpy)(PF6) 作为光氧化还原催化剂的组合,实现了非常有用的、可见光驱动的芳基溴化物和氯化物与 CO2 的羧化。该羧化反应在 1 个大气压的 CO2 下与各种官能化的芳基溴化物和氯化物以高产率进行,无需使用化学计量的金属还原剂。
Mild Esterification of Carboxylic Acids via Continuous Flow Diazotization of Amines
作者:Clément Audubert、Hélène Lebel
DOI:10.1021/acs.orglett.7b02231
日期:2017.8.18
A new continuousflow protocol for the diazotization of methylamine with 1,3-propanedinitrite in THF is reported. The synthesis of methyl esters was achieved in high yields from a variety of carboxylic acids in 20 min at 90 °C. Additionally, this protocol was extended to other aryl and alkyl amines, namely secondary amines, to produce various substituted esters in high yield using 2-MeTHF as a solvent
Electrophotocatalytic diamination of vicinal C–H bonds
作者:Tao Shen、Tristan H. Lambert
DOI:10.1126/science.abf2798
日期:2021.2.5
carbon-hydrogen (C–H) bonds to carbon–nitrogen (C–N) bonds is a highly valued transformation. Existing strategies typically accomplish such reactions at only a single C–H site because the first derivatization diminishes the reactivity of surrounding C–H bonds. Here, we show that alkylated arenes can undergo vicinal C–H diamination reactions to form 1,2-diamine derivatives through an electrophotocatalytic strategy
α-Sulfinyl Benzoates as Precursors to Li and Mg Carbenoids for the Stereoselective Iterative Homologation of Boronic Esters
作者:Giorgia Casoni、Murat Kucukdisli、James M. Fordham、Matthew Burns、Eddie L. Myers、Varinder K. Aggarwal
DOI:10.1021/jacs.7b05457
日期:2017.8.30
blocks to be converted into lithium (t-BuLi) and magnesium (i-PrMgCl·LiCl) carbenoids in the presence of boronicesters, thus allowing efficient and highly stereospecific homologation. The use of magnesium carbenoids allows carbon chains to be grown with the incorporation of sensitive functional groups, such as alkyl/aryl halides, azides, and esters. The use of lithium carbenoids, which are less sensitive
Enantioselective synthesis of α-phenyl- and α-(dimethylphenylsilyl)alkylboronic esters by ligand mediated stereoinductive reagent-controlled homologation using configurationally labile carbenoids
作者:Adam L. Barsamian、Zhenhua Wu、Paul R. Blakemore
DOI:10.1039/c5ob00159e
日期:——
with a combination of O-(α-lithiobenzyl)-N,N-diisopropylcarbamate and ligand 3,3-bis[(4S)-4,5-dihydro-4-isopropyloxazol-2-yl] pentane in toluene solvent (−78 °C to rt) with MgBr2·OEt2 additive. Enantioenrichedα-(dimethylsilylphenylsilyl)alkylboronates were obtained in 35–69% yield and 9–57% ee by reaction of B-alkyl pinacol boronates with a combination of lithio(dimethylphenylsilyl)methyl 2,4,6-triisopropylbenzoate