DIASTEREOSELECTIVE IMINO ESTER CYCLOADDITIONS - ENANTIOSELECTIVE SYNTHESIS OF AZABICYCLO[2.2.1]HEPTENES

The diethylaluminium chloride-catalysed cycloaddition of cyclopentadiene to the (S)-lactate-derived N-toluene-p-sulfonyliminoacetate 5 gives mainly (76% diastereoisomeric excess, d.e.) the adduct 9 (X-ray structure); the (R)-pantolactone-derived iminoacetate 6 similarly gives (70% d.e.) the adduct 8 which is correlated via the methyl esters 11 with compound 9.