Synthesis of Allylboranes via Cu(I)-Catalyzed B–H Insertion of Vinyldiazoacetates into Phosphine–Borane Adducts
作者:Denis Drikermann、Robert S. Mößel、Walid K. Al-Jammal、Ivan Vilotijevic
DOI:10.1021/acs.orglett.9b04619
日期:2020.2.7
Cu(I) catalysts enable C-B bond formation via direct insertion of vinyldiazoacetates into B-H bonds of borane-phosphine Lewis adducts to form phosphine-protected allylboranes under mild conditions. The resulting allylborane-phosphine Lewis adducts can be used in the diastereoselective allylation of aldehydes directly without the need for removal of the phosphine. The allylation reaction proceeds with
Vinyldiazo compounds undergo a thermal electrocyclization to form pyrazoles in yields of up to 95%. The reactions are operationally simple, use readily available starting materials, require no intervention of a catalyst, and enable the synthesis of mono-, di- and tri-substituted pyrazoles. With the ability to produce highly substituted pyrazoles and the flexibility in installing various types of substituents
Photoinduced Copper‐Catalyzed Asymmetric Decarboxylative Alkynylation with Terminal Alkynes
作者:Hai‐Dong Xia、Zhong‐Liang Li、Qiang‐Shuai Gu、Xiao‐Yang Dong、Jia‐Heng Fang、Xuan‐Yi Du、Li‐Lei Wang、Xin‐Yuan Liu
DOI:10.1002/anie.202006317
日期:2020.9.21
photoinduced copper‐catalyzed asymmetric radical decarboxylative alkynylation of bench‐stable N‐hydroxyphthalimide(NHP)‐type esters of racemic alkyl carboxylic acids with terminal alkynes, which provides a flexible platform for the construction of chiral C(sp3)−C(sp) bonds. Critical to the success of this process are not only the use of the copper catalyst as a dual photo‐ and cross‐coupling catalyst but
We describe herein a regioselective palladium(II)-catalyzedintermolecularhydroarylation of unactivated aliphatic alkenes with electronically and sterically diverse (hetero)arylsilanes under redox-neutral conditions. A removable bidentate 8-aminoquinoline auxiliary was readily employed to dictate the regioselectivity, prevent β-hydride elimination, and facilitate protodepalladation. This silicon-based
1,3-Dithietane-2-carboxylic acids and the preparation thereof
申请人:Yamanouchi Pharmaceutical Co., Ltd.
公开号:US04198339A1
公开(公告)日:1980-04-15
Substituted 1,3-dithietane-2-carboxylic acid derivatives useful as intermediates for the preparation of highly effective penicillin and cephalosporin derivatives and the preparation thereof.