| Abstract
| - We have achieved the total synthesis of (−)-mniopetal E, a drimane sesquiterpenoid which inhibitsthe reverse transcriptase of human immunodeficiency virus (HIV)-1. Our enantiospecific totalsynthesis of this target molecule in naturally occurring form commenced with a known 2,3-anhydro-d-arabinitol derivative, which was prepared using the Sharpless asymmetric epoxidation strategy.The key steps of our total synthesis were as follows: (1) a combination of highly stereocontrolledinter- and intramolecular Horner−Emmons carbon elongations for construction of a butenolidetethering a 1,2,4,9-functionalized nona-5,7-diene moiety at the β-carbon, (2) stereoselective thermalintramolecular Diels−Alder reaction of the thus-formed trienic compound, providing preferentiallyan endo-cycloadduct with the desired π-facial selection, and (3) efficient transformation of theγ-lactone moiety in the major cycloadduct to the γ-hydroxy-γ-lactone part in mniopetal E. Ourtotal synthesis of (−)-mniopetal E established the unsettled absolute stereochemistry of theantibiotic.
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