The conversion of natural (+)-aromadendrene into chiral synthons-I

Synthesis of chiral methyl-branched linear pheromones starting from (+)-aromadendrene. Part 7

“…11 These ketones can be prepared from the distillation residue of the oil of Eucalyptus globulus 12 as shown by Gijsen et al 2 The Baeyer -Villiger reaction of apoaromadendrone (6) went very well and lactone 2 was obtained in nearly quantitative yield (Scheme 2). However, attempts to open the cyclopropane ring with concentrated HCl in EtOH only led to opening of the lactone ring.…”

“…2 Conversion of the hydroxyl group in 5 to a good leaving group, followed by Baeyer -Villiger oxidation or the other way round, again should lead to lactone 3 and after Grob fragmentation and hydrogenation, 4 should be obtained.…”

Development of Novel Cyclizations <i>via</i> Rhodacycle Intermediate and Its Application to Synthetic Organic Chemistry

“…Encouraged by these results, we therefore planned for the synthesis of (±)-epiglobulol [44][45][46] using bicyclic compound 21b as a key intermediate (Chart 16). Ketalization of 21b followed by hydrolysis of esters and decarboxylation gave mono carboxylic acid 22.…”

“…45) Finally, (±)-apoaromadendrone (27) was converted into (±)-epiglobulol (28) by use of MeLi according to a method described in the literature 45) (Chart 16). 49) Guanacastepenes have attracted the interest of synthetic chemists around the world due to their unique structural features, which include two ring-junction quaternary methyl groups and a 5-7-6 tricyclic carbon skeleton [50][51][52][53] (Chart 17).…”

Crystal and molecular structure of (+)-[1aR-(1a?,3a?,7?,7a?,7b?)]-decahydro-3a-hydroxy-1,1,7-trimethyl-1H-cyclopropa-[a]naphthalen-4-one, C14H22O2

“…(+)-Aromadendrene (2) is a sesquiterpene, which occurs in large quantities in the oil of Eucalyptus globulus and is a potential raw material for the synthesis of other sesquiterpenes (Gijsen et al, 1990(Gijsen et al, , 1991(Gijsen et al, , 1992. The ~-hydroxy ketone (1) can be synthesized from (-)apoaromadendrone (3) in three steps in almost quantitative yield and might be used in the synthesis of related sesquiterpenes with a maaliane, aristolane or eudesmane skeleton (Gijsen et al, 1993).…”