Enantioselective complexation of carbohydrate or crown ether hosts with organic ammonium ion guests detected by FAB mass spectrometry

Enantioselective host-guest complexation has been demonstrated by FAB mass spectrometry. Among several carbohydrates, a modified β-mannofuranoside 6b as well as chiral crown ethers 10 and 13, differentiates a chiral ammonium ion guest such as the (1-(1-naphthyl)ethyl)ammonium ion. The relative peak intensity (RPI) method has been applied to the evaluation of such diastereomeric complex ions where the peak intensity of the target host (M)-guest (A + ) complex ion I((M+A) + ) is compared to that of the internal standard host (R)-guest (A + ) ion I((R+A) + ): the RPI value=I((M+A) + )/I((R+A) + )