cis-Diamines as active catalysts for the decarboxylation of oxalacetate

Abstract

3-endo-Dimethylaminomethyl-1,7,7-trimethylnorbornan-2-endo-amine (cis-1) and 3-endo-dimethylaminomethyl-1,7,7-trimethylnorbornan-2-exo-amine (trans-1), and the related acyclic 1,3-diamines have been examined for their catalytic activities in the decarboxylation of oxalacetate. The most active catalyst was found to be cis-1 involving the Schiff base intermediate. Available evidence indicated that a neighbouring cis configuration of two amino groups has dual functions: (1) the activation of the primary amino group by lowering the pK_a for the formation of the Schiff base intermediate at neutral pH, and (2) the stabilization of the Schiff base intermediate by electrostatic and/or hydrogen bonding.