Process for preparing hydroxychomanones and cis-aminochromanols

The present invention relates to the preparation of enantiomerically enriched hydroxychromanones by the AlCl -catalyzed intramolecular Friedel-Crafts acylation of the corresponding 3-phenoxy-2-alkylcarbonyloxy-propionic acid followed by cleavage of the carboxylate in the presence of an alkali metal peroxide or hydroperoxide. The present invention further relates to the preparation of enantiomerically enriched cis-aminochromanols by the diastereomeric reduction of oximes derived from the hydroxychromanones. The cis-aminochromanols are useful as intermediates in the preparation of HIV protease inhibitors. Enantiomerically enriched hydroxychromanones are obtained by the AlCl-catalyzed intramolecular Friedel-Crafts acylation of the corresponding 3-phenoxy-2-alkylcarbonyloxy-propionic acid followed by cleavage of the carboxylate in the presence of an alkali metal peroxide or hydroperoxide. Enantiomerically enriched cis-aminochromanols can then be prepared by treating the hydroxychromanones with a hydroxylamine and hydrogenating the resulting oxime. The cis-aminochromanols can be employed as intermediates in the production of HIV protease inhibitors which are useful for treating HIV infection and AIDS.