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A short stereoselective synthesis of the acetoxy azetidinone (1), an important precursor of several biologically active beta-lactam antibiotics, has been accomplished in seven steps and 32.8% overall yield from the easily available and inexpensive (R) ethyl 3-hydroxybutanoate.

Highly stereoselective C[sbnd]C bond forming reactions can be performed with a variety of optically active sulfinyl derivatives to afford, after desulfurization, optically active sulfur-free products.

The enantiomeric composition of derivatives of new classes of optically active sulphur compounds (variously substituted sulphoxides, sulphoximes, sulphilimines) has been readily determined with the aid of chiral europium shift reagents.

The sulfinyl group is characterized by the presence of ligands very different from each other from the stereoelectronic point of view: the lone-pair, the oxygen and two aryl or alkyl groups. This accounts for the generally high stereoselectivity met with in reactions involving chiral or prochiral groups α or β to the sulfur moiety. Transmission of chirality from sulfur to carbon has been observed i) in the α-hologenation of sulfoxides, ii) in the addition of nucleophiles and electrophiles to α, β unsaturated sulfoxides, iii) in the formation of allenic sulfoxides, and iv) in the reduction of alkylidensulfinamides and of β-ketosulfoxides. The high degree of asymmetric induction allows in most cases to rationalize the absolute configuration of the reaction products in terms of mechanism and steric factors.