The Wender Cedrene Synthesis Revisited: A Catalytic Enantioselective Entry to the Chiral Key Intermediate
作者:Hans-Günther Schmalz、Julia Westphal、Christian Schumacher
DOI:10.1055/s-0036-1588602
日期:——
The seminal synthesis of the sesquiterpene (±)-α-cedrene reported by Wender in 1981 offers a uniquely short and elegant access to the bridged-tricyclic target compound by exploiting an intramolecular arene-olefin photocycloaddition. However, the synthesis was performed only in the racemic series so far. This synthesis was now re-investigated and the catalytic methods for the enantioselective preparation
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