Abstract Enantiomers of the title intramolecular amine–borane complex with a B-pentafluoropropionyloxy ligand were resolved by chiral HPLC. X-ray analysis of the (+)-isomer revealed that the configuration of the chiral boron center was S by the Bijvoet method. Thus, the absolute configuration of this chiral borane compound was established as (S)-(+) or (R)-(−).