An efficient derivation of the title compound has been formulated from easily accessible 10-undecenoic acid(1). Thus, dodec-11-en-2-ol (3), prepared from 1, was pyranylated and subjected to bromination with NBS followed by acetolysis to furnish (2E)-1-acetoxy-11-(tetrahydropyranyloxy)-dodec-2-ene (5). Its hydrolysis, oxidation, and depyranylation afforded the (2E)-hydroxy ester (9). This, on Candida rugosa lipase-catalyzed acetylation, SeO2 oxidation, hydrolysis, and Yamaguchi macrolactonization, led to (R)-patulolide A (I) with 67.1% ee. The enantiomeric excess was improved to 97% by first resolving the alcohol 3 via porcine pancreatic lipase catalyzed acetylation and converting the corresponding (R)-acetate (13) to I as done above.
The total synthesis of the 18-membered lichen macrolide, (+)-aspicilin, has been accomplished utilizing the Swem oxidation, Masamune-Roush olefination, and ring-closing metathesis of a trienic ester as key steps. D-Mannitol has been utilized as the chiral pool material for the construction of the olefinic aldehyde and the Jacobsen hydrolytic kinetic resolution has been employed for the construction
A Configurational Switch Based on Iridium-Catalyzed Allylic Cyclization: Application in Asymmetric Total Syntheses of Prosopis, Dendrobate, and Spruce Alkaloids
作者:Christian Gnamm、Kerstin Brödner、Caroline M. Krauter、Günter Helmchen
DOI:10.1002/chem.200901316
日期:2009.10.12
A method for the stereoselectivesynthesis of 2,6‐disubstituted piperidines has been developed that is based on the use of an intramolecular iridium‐catalyzed allylic substitution as a configurational switch. The procedure allows the preparation of 2‐vinylpiperidines with enantiomeric excesses (ee) of greater than 99 %. As applications, total syntheses of piperidine alkaloids have been elaborated,
Studies on PPL Catalyzed Acetylation of 2-Alkanols: Its Application for the Synthesis of 2-Dodecanol and 2-Tridecyl Acetate, the Pheromones of<i>Crematogaster</i>Ants and<i>Drosophila mulleri</i>Flies
作者:Anubha Sharma、Archana S. Pawar、Subrata Chattopadhyay
DOI:10.1080/00397919608003858
日期:1996.1
Several aliphatic 2-alkanols with varying chain length has been efficiently resolved by their acetylation using vinyl acetate/PPL in diisopropyl ether. The effect of solvent polarity, position and type of unsaturation and chain length has been probed. This has led to more convenient synthesis of some insect pheromones.