Solvolysis of 9-Bromo-ω-bromolongifolene/9-bromo-longifolene: Synthesis of Longi-β-Nozigiku Alcohol/Longicyclenyl Alcohol from Japanese Sugi/Hinoki Essential Oils

Abstract

Longi-β-nozigiku alcohol 3/longicyclenyl alcohol 4 reported in Japanese sugi/hinoki essential oils, have been synthesized from longicyclene 2 using bromination as the key step. 9-Bromo-ω-bromo longifolene 5 (prepared from 2 by action of pyridine perbromide) is exposed to silver perchlorate in aqueous acetone to afford the ω-bromo-alcohol 7; refluxing 3. with Na-t-BuoH-THF gives the homoallylic alcohol 3. Solvolysis of 9-bromolongifolene 6 (prepared by bromination of 2 with NBS in CHCl₃ at reflux) with KOAc in ACOH at 75°/4 hr followed by hydrolysis furnishes longicyclenyl alcohol 4.