title: Dipolar Cycloaddition Route to Diverse Analogues of Cocaine: The 6- and 7-Substituted 3-Phenyltropanes.
abstract: In our quest for an antagonist or partial agonist of cocaine, access to certain 6- and 7-substituted 3-phenyltropanes of type I was required. Starting from 3-hydroxy-1-methyl-4-phenylpyridinium iodide, we disclose a pyridinium betaine-based dipolar cycloaddition route to tropenones of type II. In turn, we show how this intermediate can be transformed to type I products either through the copper-catalyzed conjugate addition reaction of Grignard reagents to the enones 7-9 or by the copper(I)-catalyzed cross coupling reaction of the allylic acetates 15a and 16a with Grignard reagents.
authors.affiliation: Georgetown University Medical Center, Institute for Cognitive and Computational Sciences, 3970 Reservoir Road NW, Washington, DC 20007-2197, and Merck Sharp & Dohme Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065.
authors.forename: Alan P.
authors.initials: AP
authors.lastname: Kozikowski
authors.forename: Gian Luca
authors.initials: GL
authors.lastname: Araldi
authors.forename: Richard G.
authors.initials: RG
authors.lastname: Ball