Enantioselective Synthesis of 1-Nitrotricyclo[5,2,2,02,6]undeca-3,8-dienes via Tandem Consecutive Asymmetric Diels-Alder Reaction-Cope Rearrangement.

Abstract The 1-glyco-2-nitrocyclohexa-2,4-dienes 1a and 5a react with cyclopentadiene to yield, almost exclusively, the 10-glyco-1-nitrotricyclo[5,2,2,02,6]undeca-3,8-dienes 4a and 8a. Formation of these products is explained as the result of a tandem consecutive asymmetric Diels–Alder reaction–Cope rearrangement. Periodate oxidation of deprotected sugar side-chains, followed by sodium borohydride reduction yielded enantiomerically pure 10-formyl- and 10-hydroxymethyl-1-nitrotricyclo[5,2,2,02,6]undeca-3,8-dienes. Structures have been determined by X-ray crystallographic and spectroscopic analyses, and chemical correlation.