HALOGEN ATOM TRANSFER ANNULATIONS INVOLVING IODOMALONATES AND ALLYLAMINE DERIVATIVES

The use of carbon radical initiated cyclizations and annulations is currently a subject of intense synthetic re-search.1-4 Recently, halogen atom transfer annulations have been described1bwherein initial halogen atom abstraction from a donor group is followed by intermolecular addition to an acceptor olefin, followed by intramolecular cyclization to afford a variety of annulated molecular frameworks. A representative example is shown in Scheme I. 5This methodology is particularly useful when an initial slow addition reaction (e.g. 1’ + 2-3) must precede a fast intramolecular closure (3-4). Additionally, since halogen is transferred to a new center in the product 5, this retained functionality may be useful for subsequent reactions (vide infra). © 1990, American Chemical Society. All rights reserved.