Reaction mechanism change in the Lewis acid catalyzed perezone-pipitzol transformation
作者:I. H. Sanchez、R. Yanez、R. Enriquez、P. Joseph-Nathan
DOI:10.1021/jo00326a052
日期:1981.6
An Oxidative Dearomatization-Induced [5 + 2] Cascade Enabling the Syntheses of α-Cedrene, α-Pipitzol, and <i>sec</i>-Cedrenol
作者:Jason C. Green、Thomas R. R. Pettus
DOI:10.1021/ja109925g
日期:2011.2.9
biosynthesis of the tricyclic skeleton of cedrol (12). The key transformation begins with the oxidativedearomatization of curcuphenol (5a) followed by an intramolecular [5 + 2] cycloaddition of the respective phenoxonium intermediate across the tethered olefin. The benzylic stereocenter effectively guides the formation of the first two stereocenters during the [5 + 2] reaction. The cascade then terminates with
α and β-pipitzols isolated from the roots of Perezia cuernavacana and obtained by thermal rearrangement of perezone, (II), have been shown to be sesquiterpenes with structures IIIa and IVa related to cedrene (XXIII). The structure of perezinone has been revised and established as shown in formula XXVI.