Catalytic atom-transfer radical cyclization by copper/bipyridine species encapsulated in polysiloxane gel.
Novel polysiloxane gel, in which CuCl/bipyridine species are immobilized, is prepared by treatment of polymethylhydrosiloxane with 4,4'-bis[(2-propenyl)oxy]-2,2'-bipyridine and 1,5-hexadine in the presence of Karstedt's catalyst followed by addition of CuCl. This polysiloxane gel acts as a reusable catalyst in the atom-transfer radical cyclization of alpha-halogenated acetamide derivatives in high turnover numbers without allowing leakage of the metal species.
Institute for Materials Chemistry and Engineering, Kyushu University, Kasuga, Fukuoka 816-8580, Japan.
Yukihiro
Y
Motoyama
Kazuyuki
K
Kamo
Akihiro
A
Yuasa
Hideo
H
Nagashima