U. Wille, O. Krüger, André Kirsch
Nov 1, 1999
Citations
0
Influential Citations
10
Citations
Journal
European Journal of Organic Chemistry
Abstract
Addition of N-bromophthalimide (1) to alkynes 3 via phthalimidyl radicals 2 introduces a bromine atom and an imidyl moiety to vicinal C atoms, and highly functionalized alkenes 5 are generated. The regioselectivity of the radical attack is controlled by steric and electronic effects, whereas the stereochemistry at the newly formed CC double bond can be explained by the Curtin–Hammett principle. When this free-radical addition is applied to the medium-sized cycloalkyne 8, the regular addition product 9 is obtained in addition to products resulting from a transannular cyclization. Furthermore, a parallel bromine radical chain is initiated to yield the highly brominated products 11 and 12.