DOI: 10.1016/j.tetasy.2010.02.023

A theoretical analysis of the conformational space of tris(2-methylbenzimidazol-1-yl)methane

The conformation surface of tris(2-methylbenzimidazol-1-yl)methane has been explored locating four minima (uuu, uud, udd and ddd, each one corresponding to two enantiomers, the P and the M) and seven transition states. The known experimental barrier to racemization (119 kJ mol⁻¹) was calculated to be about 110 kJ mol⁻¹ (uuu or uud stereoisomers). GIAO calculations of absolute shieldings correlate very well with¹H and ¹³C NMR chemical shifts. Finally, the specific rotation of the four minima was calculated allowing us to identify the absolute configuration of the first eluted enantiomer.