Marju Laars

Tertiary Thiols from Allylic Thiocarbamates by Tandem Enantioselective [3,3]-Sigmatropic Rearrangement and Stereospecific Arylation

The synthesis of tertiary thiols in enantiomerically enriched form is accomplished by lithiation of enantiomerically enriched N-aryl allylic thiocarbamates. Formation of an allyllithium derivative promotes intramolecular N to C aryl migration to the position α to sulfur, generally with good stereospecificity. The substrates may themselves be obtained by Pd-catalyzed enantioselective [3,3]-sigmatropic rearrangement of N-aryl O-allyl thiocarbamates. Solvolysis of the product thiocarbamates yields tertiary thiols, which may be converted to sulfide derivatives.

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.