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Stereochemical Characterization of Polyketide Stereotriads Synthesized via Hydrogen-Mediated Asymmetric
Mathilde Pantin1, Jonathan G Hubert1, Tilo Söhnel1
1School of Chemical Sciences, The University of Auckland , 23 Symonds Street, Auckland 1010, New Zealand.
Abstract:
The stereoselective access to stereotriads as important polyketide building blocks is reported on the basis of the Krische-type hydrogen-mediated syn-crotylation. The products were obtained with an extremely high diastereoselectivity (dr >99:1), and the newly formed syn stereocenters were controlled solely by the chiral catalyst. The stereochemistry was assigned by crystallography and HPLC for both product manifolds. This extension of the burgeoning transfer hydrogen methodology gives divergent asymmetric access to anti,syn and syn,syn polyketide stereotriads from the same α-chiral starting material and avoids potentially epimerizable aldehyde intermediates.
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