Synthesis of 3,4-disubstituted maleimides by selective cross-coupling reactions using indium organometallics.

Unsymmetrical 3,4-disubstituted maleimides have been synthesized by palladium-catalyzed cross-coupling reactions of indium organometallics with 3,4-dihalomaleimides. The synthesis was performed by stepwise or sequential one-pot palladium-catalyzed cross-coupling reactions with various triorganoindium reagents. This method was used to prepare a wide variety of alkyl, aryl, heteroaryl, and alkynyl 3,4-disubstituted maleimides in good yields and with high selectivity and atom economy.