Stereoselective Synthesis of 3-Aryloctahydroindoles and Application in a Formal Synthesis of (-)-Pancracine

A stereoselective synthesis of 3-arylociahydroindoles from enantiomerically enriched gamma-nitroketones has been developed. Reduction of imines derived form the nitroketones provides the trans-fused octhaydroindole motif selectively. The cis-octahydroindole skeleton is accessible by an invertive cyclization strategy involving a diastereomerically pure nitromesylate intermediate. This approach was employed in the synthesis of an advanced intermediate to (-)-pancracine. The gamma-nitroketone starting materials are readily available via an organocatalytic Michael reaction.