Highly regioselective synthesis of trisubstituted allenes via lithiation of 1-aryl-3-alkylpropadiene, subsequent transmetalation, and Pd-catalyzed Negishi coupling reaction.
A novel methodology for the synthesis of trisubstituted allenes is reported. Lithiation of 1-aryl-3-alkylpropadienes and subsequent transmetalation with zinc bromide followed by Pd-catalyzed Negishi coupling reactions with halides afforded the corresponding trisubstituted allenes in a highly regioselective fashion with moderate to excellent yields. A plausible regioselective lithiation mechanism was proposed on the basis of deuterium labeling experiments.
Zhao
Jinbo
J
Shanghai Institutre of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, People's Republic of China.
Liu
Yu
Y
Ma
Shengming
S