Axially Chiral Macrocyclic E-Alkene Bearing Bisazole Component Formed by Sequential C–H Homocoupling and Ring-Closing Metathesis

Clipping by ring-closing metathesis freezes rotation of a C–C bond to result in forming axial chirality. Treatment of bisbenzimidazole bearing an N-(3-butenyl) substituent with a Grubbs’ catalyst undergoes ring-closing metathesis, in which the stereochemistry of the thus formed olefin was exclusively E-form. Analysis by HPLC with a chiral stationary column confirmed clear baseline separation of each enantiomer.