SYNTHESIS AND SYNTHESIS-BASED STRUCTURAL ELUCIDATION OF (-)-MACROSPHELIDES J AND K

Abstract

The structures of (-)-macrosphelides J and K have been elucidated via asymmetric total syntheses. Key points of the structure elucidation include an initial prediction of the stereochemistries of (-)-macrosphelides J and K based on the structural relationship of the macrosphelides and molecular modeling of macrosphelide B. Our synthetic approach features an isoxazoline-based route involving a diastereoselective olefin-nitrile oxide cycloaddition, an intricate reductive N-O bond cleavage of an isoxazoline and O-alkylation of the labile beta-hydroxy ketone intermediate.