Diastereoselectivity in the intramolecular nitrone, oxime, and nitrile oxide cycloaddition reactions. Synthesis of amino inositol derivatives as α-glucosidase inhibitors
摘要:
The diastereoselectivity in the intramolecular 1,3-dipolar cycloaddition reactions of 4 and 5 (R = Bn, 4-MeOBn) was examined.
A thorough reinvestigation of the hydroboration-oxidation of methylene epoxycyclohexane 3 has revealed the formation of a direct precursor of the hitherto unreported 5-epi-cyclophellitol. Hydroboration of the starting precursor 3 takes place with total and opposite stereocontrol to that previously described in the literature. The sterochemistry of this new cyclophellitol isomer has been unambiguously confirmed by comparison with reference compounds obtained by independent methods. (c) 2007 Elsevier Ltd. All rights reserved.