rac-2,2′-Bipiperidine-1,1′-diium dibromide

In the title compound, C10H22N2 2+·2Br−, a precursor in the synthesis of organocatalysts, the bipiperidinium ion is located on a twofold rotation axis which passes through the mid-point of the central C—C bond. The piperidinium ring adopts a chair conformation. In the crystal, the cations are linked together by Br− ions through N—H⋯Br hydrogen bonds, forming layers parallel to the ab plane

Remote Activation of the Nucleophilicity of Isatin

The concept of the remote activation of reactivity was first applied in asymmetric organocatalysis. An isatin 3-phenylimine derivative acts as a donor in the thiourea catalyzed asymmetric addition to unsaturated 1,4-ketoesters, affording aza-Michael adducts in high enantiomeric purity and yield