Synthesis of natural oxygenated monocarbocyclic sesquiterpenoids from 6,7-epoxygeranyl acetate

Natural sesquiterpenes 5-(2/,5'-epoxy-2',6',6'-trimethyl)cyclohexyl-3-methy l-1-penten-3-ol (5), cis-3-[(E)-5'-hydroxy-3'-methyl-3'-pentenyl]-2,2-dimet hyl-4-methylenecyclohexanol (elegansidiol) (6), 4-(5'-acetoxy-2',6',6'-trim ethyl)cyclohex-2'-enyl-3-methyl-1-penten-3-ol (7) and 5-acetoxy-3-(3-hydrox y-3-methylpent-4-enyl)2,4,4-trimethylcyclohex-2-enone (8) were prepared fro m 6,7-epoxygeranyl acetate (9), via (2',5'-epoxy-2',6',6'-trimethyl)cyclohe xylmethyl tosylate (10), for the first time. 5 is an intermediate in the sy nthesis of the sesquiterpene-coumarin ether (+/-)-farnesiferol C (1). The p reparation of suitable intermediates for synthesising related natural farme siferol B (3) and D (4) is also reported. (C) 2000 Elsevier Science Ltd. Al l rights reserved.