N-Boc Amines to Oxazolidinones via Pd(Ⅱ)/Bis-sulfoxide/Bronsted Acid Co-Catalyzed Allylic C-H Oxidation

摘要

A Pd(Ⅱ)/bis-sulfoxide/Bronsted acid catalyzed allylic C-H oxidation reaction for the synthesis of oxazolidinones from simple N-Boc amines is reported. A range of oxazolidinones are furnished in good yields (avg 63%) and excellent diastereoselectivities (avg 15∶1) to furnish products regioisomeric from those previously obtained using allylic C-H amination reactions. Mechanistic studies suggest the role of the phosphoric acid is to furnish a Pd(Ⅱ)bis-sulfoxide phosphate catalyst that promotes allylic C-H cleavage and π-allylPd functionalization with a weak, aprotic oxygen nucleophile and to assist in catalyst regeneration.