Doubly activated cyclopropanes as synthetic precursors for the preparation of 4-nitro- and 4-cyano-dihydropyrroles and pyrroles.
[reaction: see text] 1-Nitro- and 1-cyano-cyclopropyl ketones have been prepared in an expedient manner from cyclopropanation reactions of alkenes by diazo compounds or in situ-generated phenyliodonium ylides catalyzed by Rh(II) carboxylates. The doubly activated cyclopropanes were used as synthetic precursors for the regiospecific synthesis of 4-nitro- and 4-cyano-dihydropyrroles upon treatment with primary amines. Oxidation of the dihydropyrroles with DDQ allows rapid access to densely functionalized pyrroles.
Wurz
Ryan P
RP
Département de Chimie, Université de Montréal, P. O. Box 6128, Station Downtown, Montréal, Québec, Canada H3C 3J7.
Charette
André B
AB