metal-free reductionsystem, in which H2Se (or HSe–) produced in situ from Se/DMF/H2O acts as the active reducing species, has been developed. By using water as an inexpensive, safe, and environmentally friendly surrogate as the hydrogen donor, this newreductionsystem incorporating Se/DMF/H2O displayed high selectivity and good activity in the reduction of α,β-unsaturated ketones and alkynes. Therefore
一种新型的无金属还原系统,其中H 2 SE(或HSE组- )原位产生从硒/ DMF / H 2 ö充当活性还原物质,已经研制成功。通过使用水作为廉价,安全和环保的替代物作为氢供体,这种结合了SE / DMF / H 2 O的新还原系统在还原α,β-不饱和酮和炔烃方面显示出高选择性和良好的活性。因此,该还原系统具有很大的潜力,可以作为有机转化中通用而实用的还原方法。
Synthesis and characterization of novel chiral NHC–palladium complexes and their application in copper-free Sonogashira reactions
作者:Longguang Yang、Pei Guan、Pan He、Qian Chen、Changsheng Cao、Yu Peng、Zhan Shi、Guangsheng Pang、Yanhui Shi
DOI:10.1039/c2dt12391f
日期:——
A new series of chiral N-heterocyclic carbene (NHC) palladium complexes were synthesized from a relatively inexpensive amino acid, L-phenylalanine. All these compounds were fully characterized by 1H-NMR, 13C-NMR and elemental analysis. The X-ray molecular structures of two of the complexes were reported. The catalytic activity of the four palladium complexes was successfully tested in the Sonogashira reaction under copper free conditions in air. The palladium complex 3a provided good activity in the Sonogashira coupling reaction.
Highly efficient synthesis of 1,2-disubstituted acetylenes derivatives from the cross-coupling reactions of 1-bromoalkynes with organotitanium reagents
作者:Chuan Wu、Qing-Han Li
DOI:10.1016/j.tet.2021.132370
日期:2021.9
A Highly efficient route for the synthesis of 1,2-disubstituted acetylene derivatives has been developed by nickel catalyzed cross-couplings of alkynyl halides with aryl titanium reagents under mild conditions. This has given corresponding cross-coupling products good to excellent isolated yields of up to 92 %. The aryls bearing electron-donating or electron-withdrawing groups in either alkynylhalides
A catalyst-free and transition-metal-free method for the synthesis of 1,2-diketones from aerobic alkyne oxidation was reported. The oxidation of various internal alkynes, especially more challenging aryl-alkyl acetylenes, proceeded smoothly with inexpensive, easily handled, and commercially available potassium persulfate and an ambient air balloon, achieving the corresponding 1,2-diketones with up