Synthesis based on cyclohexadienes: Part 101 synthesis of 5,5'-dimethyl-7-methoxy-4-oxatricyclo[4.3.1.03,7]decan-2-ones

Article abstract of DOI:10.1016/S0040-4020(01)86976-3

Synthesis of 5,5-dimethyl-7-methoxy-4-oxatricyclo[4,3,1,0^3,7]-decan-2-one 3a, a novel heterocyclic ring system present in morellin 1, and its 3-substituted derivatives 3b-e, is described from the Diels-Alder adducts 7, available from 1-methoxycyclohexa-1,4-dienes 4. Two routes, which involved the halocyclisation and the oxidative addition, were investigated for the conversion of the adducts 7 into 3. While the halocyclisation method resulted in mixtures, excellent yields of the target molecule were obtained by the second method. Solvolysis of the bromoether 9 resulted in a mixture of rearrangement products 10, 13, 15 and 16.