Some cationic η3-propargylpalladium complexes were prepared upon treatment of the corresponding η1-propargyl- or η1-allenylbis(triphenylphosphine)palladium(II) chloride with Ag[BF4] or Na[BPh4]. The effectiveness of the latter reagent suggests that a η1-propargyl- or η1-allenyl(chloro)palladium complex equilibrates with a cationic η3-propargylpalladium complex with the liberation of a Cl− ligand. A
Selective Propargylation of Azo Compounds with Barium Reagents
作者:Akira Yanagisawa、Takanori Koide、Kazuhiro Yoshida
DOI:10.1055/s-0029-1219944
日期:2010.6
A Barbier-type propargylation of azo compounds with γ-trialkylsilylated propargylic bromides has been achieved using reactive barium as a low-valent metal in THF. Corresponding propargylated hydrazines (α-adducts) were exclusively formed not only from azobenzenes (diaryldiazenes) but also from dialkyl azodicarboxylates. This method is also applicable to γ-alkylated or γ-phenylated propargylic bromides
The Renaissance of an Old Problem: Highly Regioselective Carboxylation of 2-Alkynyl Bromides with Carbon Dioxide
作者:Bukeyan Miao、Gen Li、Shengming Ma
DOI:10.1002/chem.201503494
日期:2015.11.23
A steric effect‐controlled, zinc‐mediated carboxylation of different 2‐alkynyl bromides under an atmosphericpressure of CO2 has been developed by careful tuning of different reaction parameters, including the metal, solvent, temperature, and additive. 2‐Substituted 2,3‐allenoic acids were afforded from primary 2‐alkynyl bromides, whereas the carboxylation of secondary 2‐alkynyl bromides yielded 3‐alkynoic