Diastereoselective synthesis of optically active rotaxane amine N-oxides via through-space chirality transfer.

Selective synthesis of optically active rotaxane amine N -oxides was achieved with high diastereoselectivity via the effective through-space chirality transfer. Oxidation of tert -amine moiety on axle component of rotaxane with an optically active wheel component having ( R )-binaphthyl group was carried out. The oxidation of several rotaxanes with dimethyldioxirane was conducted in dichloromethane at −78 °C to give the corresponding amine N -oxides with high diastereoselectivity up to 95%, indicating the conversion via the effective through-space chirality transfer. Higher diastereoselectivity was observed with the rotaxane possessing the rigid skeleton and the N -benzyl substituent. The optimized structures suggested the stereochemistry of the nitrogen center of ( R )-configuration. [ABSTRACT FROM AUTHOR]