Retro-Mannich reactions of 3-alkyl-3,4-dihydro-2H-1,3-benz e oxazines and the synthesis of axially chiral resorcinarenes

Abstract Intermediates involved in the conversion of 3-alkyl-3,4-dihydro-2 H -1,3-benz[ e ]oxazines into 2- N , N -dialkylaminomethylphenol derivatives, using morpholine and other high boiling secondary amines, have been identified and characterised. Additional experiments have established the involvement of o -quinone methide intermediates in the retro-Mannich reactions. Axially chiral resorcinarenes have been prepared by utilising the exchange reactions.