Chiral chalcogen compounds

In this chapter, recent development on the synthesis and stereochemistry of optically active chalcogen compounds over the last 10 years will be described, focusing mainly on chiral selenium and tellurium compounds. 

Many optically active hypervalent chalcogen compounds, particularly sulfur compounds, have been synthesized and proposed as important key intermediates in various reactions of the chalcogen compounds.46 Since the synthesis of spirosulfurane by Kapovits and Kalman,47 many optically active spir-osulfuranes were isolated in the last decade. Spirosulfurane 28 was separated into enantiomers by kinetic resolution using a chiral host molecule and found to be optically stable by Drabowicz and Martin.48 Spirosulfurane 29 was separated into enantiomers by chromatographic method by Allenmark and Claeson, and characterized by chiroptical methods.49 Optically active... 

Certain chalcogen structures display the phenomenon of chirality (Chapter 10.2). As with carbon,2 chirality at sulfur can influence physiological events there are many stereoselectivities in the interactions of chiral sulfur compounds with enzymes and receptor molecules. Sulfur chirality in secondary metabolites is most commonly observed with sulfonium salts, sulfoxides and sulfoximines.3... 

The reaction of chiral lithiated ferrocenylamines with dialkylthiuramdisulfides leads to the corresponding (dialkylthiocarbamoyl)thioferrocenes [144]. For catalytic applications, sulfur and selenium derivatives with one [140, 141, 145] or two [146—148] chalcogen substituents have been prepared (see Sect. 4.5.3.1). The technique is essentially the same as for the chiral phosphines lithiation of enantiomerically pure lV,iV-dimethyTl-ferrocenylethylamine, followed either by the addition of a disulfide or a diselenide to the monosubstituted compounds, or by... 

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