title: Biomimetic Cyclization of Enamide-Containing Polyenes as a New Route to Azapolycycles.
abstract: Enamide 4 was studied for its effectiveness as a polyene precursor in biomimetic cyclizations. While most conventional Lewis acids were poor cyclization promoters, FeCl(3).6H(2)O initiated the conversion of 4 into tricycles 6 and 7 in excellent yield. The two isomeric products result from the cyclization of intermediate aldehyde 5 by either a chair or boat B-ring transition state. These results suggest that enamides may be incorporated into polyene precursors for the construction of larger azapolycycles such as azasteroids.
authors.affiliation: Department of Chemistry, Indiana University-Purdue University at Indianapolis (IUPUI), 402 North Blackford Street, Indianapolis, Indiana 46202.
authors.forename: Stephanie E.
authors.initials: SE
authors.lastname: Sen
authors.forename: Steven L.
authors.initials: SL
authors.lastname: Roach