Synthesis of all stereoisomers of eudesm-11-en-4-ol. 2. Total synthesis of selin-11-en-4.alpha.-ol, intermedeol, neointermedeol, and paradisiol. First total synthesis of amiteol

Abstract

The syntheses of (±)-selin-11-en-4α-ol (5), (±)-intermedeol (6), (±)-neointermedeol (7), (±)-amiteol (9), and the four remaining unnatural stereoisomers (±)-paradisiol (8), (±)-7-epi-amiteol (10), (±)-5-epi-neointermedeol (11), and (±)-5-epi-paradisiol (12) are described. In addition, the related (±)-evuncifer ether (25) has been prepared. The syntheses started from the octahydro-8-hydroxy-4a,8-dimethyl-2(1H)-naphthalenones 1-4. The reaction sequence employed for the synthesis of 5, 7, 9, and 12 involved Wittig reaction, oxidative hydroboration, oxidation, equilibration, and olefination. For the synthesis of 6, 8, 10, and 11 the interim equilibration step was omitted. The oxidative hydroboration was the key step in these syntheses.