PALLADIUM(II)-MEDIATED COUPLING REACTIONS OF BROMO-1H-1,4-BENZODIAZEPINE-2,5-DIONES AND IODO-1H-1,4-BENZODIAZEPINE-2,5-DIONES - A ROUTE TO FUNCTIONALIZED BENZODIAZEPINEDIONES

A series of 7-, 8-, and 9-bromo- and iodo-1,4-benzodiazepine-2,5-diones have been prepared and examined as substrates for palladium(II)-mediated coupling reactions with alkenes, alkynes, arylstannanes, and heteroarylstannanes. The benzodiazepinediones 6a,e,g were prepared from the reaction of o-nitrobenzoyl chlorides 3a-c and methyl tert-butylglycinate followed by nitro reduction and cyclization. Regioselective halogenation gave 6c,d,f. Bromo- and iodobenzodiazepinediones 6c,d,f,g were then converted to alkenyl-, alkynyl-, aryl-, and heteroaryl-substituted benzodiazepinediones in moderate to good yield in the presence of palladium(II).