Effect of sulfonyl protecting groups on the neighboring group participation ability of sulfonamido nitrogen.
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.
Proust
Nicolas
N
Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA.
Gallucci
Judith C
JC
Paquette
Leo A
LA