Synthesis of Alkylidene(<i>gem</i>-Difluorocyclopropanes) from Propargyl Glycolates by a One-Pot Difluorocyclopropenation/Ireland–Claisen Rearrangement Sequence
difluorocyclopropenation/Ireland–Claisenrearrangement sequence applied to readily available propargyl glycolates was developed as a route toward functionalized alkylidene(gem-difluorocyclopropanes). This strategy conveniently avoids the isolation of the unstable 3,3-difluorocyclopropenylcarbinyl glycolates arising from the difluorocyclopropenation. The Ireland–Claisenrearrangement proceeds with high
Controllable chemoselectivity in the coupling of bromoalkynes with alcohols under visible-light irradiation without additives: synthesis of propargyl alcohols and α-ketoesters
作者:Ke Ni、Ling-Guo Meng、Hongjie Ruan、Lei Wang
DOI:10.1039/c9cc04090k
日期:——
The chemoselectivity of visible-light-induced coupling reactions of bromoalkynes with alcohols can be controlled by simple changes to the reaction atmosphere.
可见光诱导的溴代炔与醇的偶联反应的化学选择性可以通过对反应气氛进行简单改变来控制。
Silver Mediated Banert Cascade with Carbon Nucleophiles
作者:Juliana R. Alexander、Paul V. Kevorkian、Joseph J. Topczewski
DOI:10.1021/acs.orglett.1c01032
日期:2021.4.16
Nickel-Catalyzed Asymmetric Friedel–Crafts Propargylation of 3-Substituted Indoles with Propargylic Carbonates Bearing an Internal Alkyne Group
The nickel-catalyzed highly enantioselective Friedel Crafts propargylation of 3-substituted indoles with propargylic carbonates bearing an internal alkyne group was developed. A wide array of the propargylic carbonates as well as 3-substituted indoles can be applicable to the asymmetric nickel catalysis, providing the corresponding chiral C-3 propargylated indolenine derivatives bearing two vicinal chiral centers in up to 89% yield with up to >99% ee and 94:6 dr (24 examples).
Intercepting the Banert cascade with nucleophilic fluorine: direct access to α-fluorinated <i>N</i>H-1,2,3-triazoles
作者:J. R. Alexander、P. V. Kevorkian、J. J. Topczewski
DOI:10.1039/d1cc01179k
日期:——
The treatment of propargylic azides with silver(I) fluoride in acetonitrile was found to yield α-fluorinated NH-1,2,3-triazoles via the Banert cascade. The reaction was regioselective and the products result from an initial [3,3] rearrangement. The reaction is demonstrated on >15 examples with yields ranging from 37% to 86%.