Synthesis of sesquiterpene allylic alcohols and sesquiterpene dienes from Cupressus bakeri and Chamaecyparis obtusa

Five muurolane (1-5), one nor-seco-muurolane (6) and one nor-muurolane (7) sesquiterpene natural products recently reported from Cupressus bakeri have been obtained by chemical synthesis together with the unnatural 7-epimeric amorphane analogues of four of these sesquiterpenes (15, 16, 18 and 19). T he conversion of sesquiterpene allylic tertiary alcohols 1, 2, 15 and 16 in to regioisomeric sesquiterpene dienes 3-5 and 17-20 was investigated in vit ro by NMR and the mechanism for such dehydrations and their relevance to th e origins of sesquiterpene dienes which have been reported as natural produ cts (such as 3-5) is discussed.