C2-Chiral Substituted cis-1,3,5,7-Tetraazadecalins as Proton Sponges:A Computational Study


  • Dedicated to Professor Benzion Fuchs, Tel-Aviv University, Israel


Density functional quantum chemical calculations at the B3LYP/6-31+G* and B3LYP/6-31+G** levels have been performed to calculate the proton affinities of chiral cis-1,5-diazadecalins 1,2 and substituted cis-1,3,5,7-tetraazadecalin 3. The calculated gas-phase proton affinities of cis-1,3,5,7-tetraazadecalins are higher than that of 1,8-bis(dimethylamino)naphthalene (4). cis-1,5-Diazadecalins show lower proton affinities compared with those of substituted 1,3,5,7-tetraazadecalins. Cooperative and anomeric effects seem to be responsible for the additional stabilization of the protonated forms of 1,3,5,7-tetraazadecalins. Intramolecular proton transfer energies have been predicted for these amines and discussed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)