Rhodium(II) catalyzed diastereoselective reactions of diazoacetamides with isatins: an efficient approach to 3-hydroxy-3,3′-bioxindoles

The 3,3'-bioxindole derivatives were constructed in a single step via an efficient Rh-2(OAc)(4) catalyzed reaction of diazoacetamides with isatins. This novel method provides an alternative pathway towards 3-hydroxy-3,3'-bioxindoles in good yield (up to 78%) with high diastereoselectivity (up to 95 : 5).