Selective mono- and 1,2-difunctionalisation of cyclopentene derivatives via Mg and Cu intermediates.
A single Br/Mg exchange of 1,2-dibromocyclopentene with iPrMgCl LiCl provides the corresponding beta-bromocyclopentenylmagnesium reagent, which can then be reacted with various electrophiles (yields: 65-82 %). In the presence of a secondary alkylmagnesium halide and Li2CuCl4 (2 mol %), these 2-bromoalkenylmagnesium compounds undergo bromine substitution and can then further react with electrophiles to give 1,2-difunctionalised cyclopentenes (63-79 %). The mechanism of this process is discussed.
Despotopoulou
Christina
C
Department Chemie und Biochemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Haus F, 81377 München, Germany.
Bauer
Richard C
RC
Krasovskiy
Arkady
A
Mayer
Peter
P
Stryker
Jeffrey M
JM
Knochel
Paul
P