Abstract
The reaction of 3-phenyl-1-azabicyclo[1.1.0]butane (1c) with 2,3-dicyanofumarates ((E)-5) in dichloromethane at room temperature yields mixtures of cis- and trans-2,3-dicyano-4-phenyl-1-azabicyclo[2.1.1]hexane- 2,3-dicarboxylates (cis,trans-4). The proposed two-step reaction mechanism via a zwitterionic intermediate of type (6) is supported by trapping experiments with methanol: when the reactions of 1-azabicyclo[1.1.0]butanes (1) with dimethyl 2,3-dicyanofumarate ((E)-5a) are carried out in methanol, dimethyl (E)-2-(azetidin-1-yl)-3-cyanobut-2-enedioates (7) are formed as the only products.
Mloston, G