477284-04-1Relevant articles and documents
Synthesis of (-)-centrolobine by Prins cyclizations that avoid racemization.
Marumoto, Shinji,Jaber, James J,Vitale, Justin P,Rychnovsky, Scott D
, p. 3919 - 3922 (2007/10/03)
[formula: see text] The segment-coupling Prins cyclization avoids two of the problems common to other Prins cyclization protocols: side-chain exchange and partial racemization by reversible 2-oxonia Cope rearrangement. Model studies demonstrate the stereochemical fidelity of Prins cyclizations using alpha-acetoxy ethers compared with direct aldehyde-alcohol Prins reactions. Furthermore, we propose a mechanism for the racemization observed in some intermolecular Prins cyclizations. Two straightforward syntheses of optically pure (-)-centrolobine highlight the utility of Prins cyclizations.