A formal synthesis of reserpine: hydrindane approach to the Woodward's ring-E precursor

A new synthetic approach to a functionally and stereochemically embellished cyclohexanoid, corresponding to the Woodward's ring-E intermediate 24 of t he complex indole alkaloid reserpine 1 is delineated. Our scheme emanates f rom a readily available endo-tricyclo[5.2.1.0(2,6)]decane system from which cis-hydrindane and cyclohexanoid moieties are sequentially extracted. The strategy outlined here exploits the propensity of the endo-tricyclo[5.2.1.0 (2,6)]decane and cis-hydrindane systems to react from the convex face to ge nerate the requisite stereochemical pattern. Since 24 has been previously e laborated to the natural product, the present effort constitutes a formal s ynthesis of rac-reserpine.