We have recently developed an efficient one-pot synthesis of symmetrical pyrrolo[3,2-b]pyrrole -2,5-diones by reaction of ester carbanions with oxalic acid-bis(imidoyl)dichlorides which can be regarded as aza-analogues of oxalyl chloride. [6] [8] The scope of this method was severely limited by the fact that only symmetrical bis(imidoyl) dichlorides were available. Herein, we wish to report the synthesis of unsymmetrical oxalic acid-bis(imidoyl) dichlorides. In addition, ...
