title: The endocyclic restriction test: the geometries of nucleophilic substitutions at sulfur(VI) and sulfur(II).
abstract: The trajectories for nucleophilic substitutions at sulfur(VI) and sulfur(II) have been investigated by the endocyclic restriction test. On the basis of double-labeling experiments, the sulfur(VI) transfer in the conversion of 1 to 2 is found to be intramolecular, while the sulfur(VI) transfer in the conversion of 3 to 4 and the sulfur(II) transfer in the conversion of 5 to 6 are found to be intermolecular. These results are taken to be consistent with transition structures for these sulfur transfer reactions which require a large angle between the entering and leaving group, a geometry analogous to apical group positions in trigonal bipyramidal transition states.
authors.affiliation: Department of Chemistry, University of Illinois, Roger Adams Laboratory, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Jarboe
authors.forename: Michael S
authors.initials: MS
authors.lastname: Terrazas
authors.forename: Peter
authors.initials: P
authors.lastname: Beak
mesh_terms: D002849:Chromatography, Gas; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D013449:Sulfonamides / Q000138:chemical synthesis; D013457:Sulfur Compounds / Q000138:chemical synthesis*
chemical_list: D007202:Indicators and Reagents; D013449:Sulfonamides; D013457:Sulfur Compounds