The Renaissance of an Old Problem: Highly Regioselective Carboxylation of 2-Alkynyl Bromides with Carbon Dioxide.
A steric effect-controlled, zinc-mediated carboxylation of different 2-alkynyl bromides under an atmospheric pressure 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 acids in decent yields. A rationale for the observed regioselectivity has been proposed.
Shanghai Key Laboratory of Green Chemistry and Chemical Process, Department of Chemistry, East China Normal University, 3663 North Zhongshan Lu, Shanghai 200062 (P. R. China).
Bukeyan
B
Miao
Department of Chemistry, Fudan University, 220 Handan Lu, Shanghai 200433 (P. R. China).
Gen
G
Li
Department of Chemistry, Fudan University, 220 Handan Lu, Shanghai 200433 (P. R. China). masm@sioc.ac.cn.|State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032 (P. R. China). masm@sioc.ac.cn.
Shengming
S
Ma
allenylation; carbon dioxide fixation; propargylation; regioselectivity; zinc