Enynylation of 2-iodo-4-(phenylchalcogenyl)-1-butenes via intramolecular chelation: approach to the synthesis of conjugated dienynes or trienynes.
[reaction: see text] 2-Iodo-4-(phenylchalcogenyl)-1-butenes 3 and 4, which are derived from methylenecyclopropanes 1, can be enynylated with alkynes catalyzed by Pd(OAc)(2) to give conjugated dienynes 5 and 6 in the absence of any phosphine ligand and copper salt, and trienyne 9a can be obtained by oxidation of compound 5a. A plausible reaction mechanism has been proposed.
Department of Chemistry, East China Normal University, Shanghai. mshi@pub.sioc.ac.cn
Min
M
Shi
Le-Ping
LP
Liu
Jie
J
Tang