Identification and determination of the absolute configuration of amorph-4-en-10β-ol, a cadinol-type sesquiterpene from the scent glands of the African reed frog Hyperolius cinnamomeoventris

• Published in: Beilstein journal of organic chemistry Vol. 19; no. 1; pp. 167 - 175
• Main Authors: Ladwig, Angelique, Kroll, Markus, Schulz, Stefan
• Format: Journal Article
• Language: English
• Published: Germany Beilstein-Institut zur Föerderung der Chemischen Wissenschaften 16.02.2023; Beilstein-Institut
• Subjects: Absolute configuration; anura; Cadinol; Chemical communication; Chemistry; chiral gas chromatography; Chromatography; enantioselective synthesis; Frogs; Full Research Paper; gc/ms; Hyperolius cinnamomeoventris; Lactones; Males; Natural products; Oxidation; Scent gland; semiochemicals; Sensory integration; Stereoisomers; VOCs; Volatile organic compounds; Anura; chiral gas chromatography; enantioselective synthesis; semiochemicals; GC/MS
• ISSN: 1860-5397; 2195-951X; 1860-5397
• DOI: 10.3762/bjoc.19.16

Hyperolid reed frogs are one of the few families of Anurans known to possess glands that emit volatile compounds used in chemical communication. , a model species, possesses a gular gland on its vocal sac that emits chemicals, and sends visual and auditory signals during calling. Previous investigations have shown that the glandular compounds are typically macrocyclic lactones. However, in this work, we show that another major constituent of the male specific gland is (10 ,1 ,6 ,7 ,10 )-amorph-4-ene-10β-ol [(1 ,4 ,4a ,8a )-4-isopropyl-1,6-dimethyl-1,2,3,4,4a,7,8,8a-octahydronaphthalen-1-ol]. This compound was synthesized for the first time and has the opposite configuration to amorph-4-ene-10β-ol known from plants. A short synthesis using an organocatalytic approach through a tandem Mannich/intramolecular Diels-Alder reaction led to a mixture of cadinols, which was used for the assignment of the natural cadinol structures and their stereoisomers.