Alkynylation of Benzotriazole with Silylethynyliodonium Triflates. Regioselective Synthesis of 2-Ethynyl-2H-benzotriazole Derivatives
摘要:
Phenyl(trimethylsilylethynyl)iodonium and tert-butyldimethylsilylethynyl(phenyl)iodonium triflates were applied to alkynylation of benzotriazole. Treatment of the silylethynyliodonium triflates with the potassium salt of benzotriazole ion in (BuOH)-Bu-t and CH2Cl2 gave 2-(trimethylsilylethynyl)-2H-1,2,3-benzotriazole and 2-(tert-butyldimethylsilylethynyl)-2H-1,2,3-benzotriazole in 74% and 76% yields, respectively. The regioisomers, 1-silylethynyl-1H-1,2,3-benzotriazole derivatives, were minor. In both cases of the silyl-substitued ethynyliodonium salts, novel regioselective alkynylation of benzotriazole at the 2 position was observed.
Photo-induced synthesis of β-sulfonyl imides from carboxylic acids
作者:Linwei Zeng、Jian Jin、Jixiao He、Sunliang Cui
DOI:10.1039/d1cc02559g
日期:——
A photo-induced imidation process of carboxylic acids is described. Numerous carboxylic acids could convert to β-sulfonyl imides in the presence of N-sulfonyl ynamides under visible light irradiation. Control experiments and mechanistic studies demonstrate that this imidation process involves a hydroacyloxylation/radical rearrangement cascade. This protocol represents a direct imidation method from
towards substituted beta- and gamma-carbolines based on transition metal catalysed [2+2+2] cycloaddition reactions between functionalised yne-ynamides and methylcyanoformate is described. The versatility of this new reaction sequence is demonstrated by its application in the totalsynthesis of the marine natural product eudistominU.
with a catalytic amount of TpRuCl(PPh3)2 resulted in the construction of indole scaffolds known as privileged structure motifs. This reaction involved a cascade of 1,2‐rearrangement and cyclization carrying out C−C bond formationvia a rutheniumvinylidene intermediate, as revealed by a deuterium‐labeling experiments. Furthermore, the transformation of multi‐functionalized ynamide, derived from a practical
Di-<i>tert</i>-butyl Ethynylimidodicarbonate as a General Synthon for the β-Aminoethylation of Organic Electrophiles: Application to the Formal Synthesis of Pyrrolidinoindoline Alkaloids (±)-CPC-1 and (±)-Alline
作者:Ramsay E. Beveridge、Yiwei Hu、Bruce Gregoire、Robert A. Batey
DOI:10.1021/acs.joc.0c00781
日期:2020.7.2
β-aminoethyl anion synthetic equivalent. It can be used to install ethyleneamine groups by exploiting its terminal alkyne reactivity with common organic electrophiles. Reactions exemplified with this terminal ynimide reagent include additions to imines, aldehydes, ketones, pyridinium salts, Michael acceptors, epoxides, and Pd-catalyzed Sonogashira couplings. Subsequent regioselective [3 + 2] cycloadditions
pyridiniums were synthesized through intramolecular cyclization, demonstrating the utility of N-alkynylpyridiniums for the design of various electron-deficient cationic nitrogen-embedded polycyclicaromatichydrocarbons with unique optical and electrochemical properties.