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 pKa 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.