Benzoxazepinones synthesis

The tricyclic sesquiterpene longifolene has served as a vehicle for the illustration of new strategies for organic synthesis.25 Both enantiomers have been obtained from natural sources (-i-)-longifolene occurs in several Firms species and is commercially available while the rare (—)-longifolene has been found in certain liver mosses.2 We elected to prepare (—)-longifolene 49 from the cyclohexa-1,4-diene 45, obtained from the Birch reduction-alkylation of benzoxazepinone 9 in 96% yield with a diastereomeric excess of greater than 98% (Scheme 13).22... 

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