Boron aldol reaction of α-halosubstituted thioacetates with silyl imines: A highly enantio- and diastereoselective synthesis of aziridines

Article abstract of DOI:10.1016/0040-4039(96)00637-5

Boron enolates derived from tert-butyl α-halothioacetate and bearing menthone-derived chiral ligands react with imines with excellent diastereo- and enantiocontrol to give syn α-halo-β-aminothioesters, which can be converted to the corresponding aziridines by simple ring closure during LAH reduction. A key precursor of antibiotics (+)-thiamphenicol and (-)-florfenicol was synthesized.