A Facile Synthesis of Optically Pure (−)-(S)-Ipsenol Using a Chiral Titanium Complex

✍ Scribed by Konrad Oertle; Harry Beyeler; Rudolf O. Duthaler; Willi Lottenbach; Martin Riediker; Eginhard Steiner

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: German
• Weight: 439 KB
• Volume: 73
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19900730215

✦ Synopsis

A stereocontrolled synthetic route to optically pure (-)-(S)-ipsenol (l), the pheromone of Pityokteines curuidens and various other bark-beetle species is described. Key step of the synthesis is an enantioselective aldol reaction using a chiral titanium-cabrohydrate complex (Scheme I). The carboxylate function of the optically pure B-hydroxy acid 5 thus obtained in mol quantities is then elaborated to the dime moiety by standard methodology (Scheme 2).

Various species of bark beetles are important pests to coniferous forests throughout the world. Among these are beetles of the genus Ips. In 1965 Silverstein et al. [2] isolated and characterized two new terpene alcohols from frass produced by Ips paraconfusus in ponderosa pine: (-)-(S)-ipsenol ( = 2-methyl-6-methylideneoct-7-en-4-01; 1) and (+)-(S)-ipsdienol ( = 2-methyl-6-methylideneocta-2,7-dien-4-ol; 2). The absolute configurations were established by Mori in 1976 by chemical correlation [3]. 1 (-)-lpsenol 2 (+)-lpsdienol ') ' ) ' ) Part 6 of 'Enatioselective Syntheses with Titanium-Carbohydrate Complexes'; part 5,