title: Effect of sulfonyl protecting groups on the neighboring group participation ability of sulfonamido nitrogen.
abstract: The addition of elemental bromine dissolved in CH(2)Cl(2) to para-disubstituted benzodiazocines where X is the same (H, CH(3), Br, OMe, NO(2)) or a different substituent as X and Y (CH(3), Br; OMe, NO(2)) has been found to proceed in most cases with competition between two pathways. While conventional trans-1,2-addition operates predominantly, electron-releasing groups also foster a ring-contraction process with ultimate 1,3-positioning of the pair of bromine atoms. The observed regio- and stereoselectivities, confirmed where necessary by X-ray crystallographic analysis, establish the capability of sulfonamide nitrogen centers to engage in neighboring group participation.
authors.affiliation: Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Proust
authors.forename: Judith C
authors.initials: JC
authors.lastname: Gallucci
authors.forename: Leo A
authors.initials: LA
authors.lastname: Paquette