Sulfonate esters are often leaving groups in nucleophilic substitution reactions. See the articles on sulfonyl and sulfonate groups for further information.
*Bs for the brosyl (p-bromobenzenesulfonyl) group; OBs is the brosylate group
*Ms for the mesyl (methanesulfonyl) group; OMs is the mesylate group
*Ns for the nosyl (p-nitrobenzenesulfonyl) group (Ns was the chemical symbol for nielsbohrium, but that was renamed bohrium, Bh); ONs is the nosylate group
*Tf for the triflyl (trifluoromethanesulfonyl) group; OTf is the triflate group
*Nf for the nonaflyl (nonafluorobutanesulfonyl) group, ; ONf is the nonaflate group
*Ts for tosyl (p-toluenesulfonyl) group (Ts is also the symbol for the element tennessine. However, tennessine is too unstable to ever be encountered in organic chemistry, so the use of Ts to represent tosyl never causes confusion); OTs is the tosylate group