Asymmetric Synthesis of Iridoid Derivatives Using Resolved 2Phenylindoline as a Chiral Auxiliary

Autor: Santangelo, Ellen M., Liblikas, Ilme, Mudalige, Anoma, Törnroos, Karl W., Norrby, PerOla, Unelius, C. Rikard
Zdroj: European Journal of Organic Chemistry; December 2008, Vol. 2008 Issue: 35 p5915-5921, 7p
Abstrakt: An asymmetric synthetic route to cis,cisnepetalactol component of the sex pheromone for the hop aphid, Phorodon humuli is presented. 2Phenylindoline was resolved to provide a chiral auxiliary for the cycloaddition of oxocitral. The resolution was made by chromatographic separation of the diastereomers of the urea derivative made from 2phenylindoline and with R+αmethylbenzyl isocyanate, followed by reductive cleavage of the isolated diasteromers using diborane. The cycloaddition of oxocitral using S2phenylindoline yielded an enantiopure product after chromatography. Hydrolysis of the cycloaddition adduct yielded gastrolactol 3. As gastrolactol is a versatile synthon for the synthesis of iridoids, the overall procedure provides a general asymmetric route to elaborated iridoids. © WileyVCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009
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