Itosilate

Itosilate, also known as para-toluenesulfonate or tosylate, is an anion with the chemical formula [CH3C6H4SO3]−. It is the conjugate base of para-toluenesulfonic acid (TsOH). In organic chemistry, the tosylate group (abbreviated as Ts or OTs) is a good leaving group, making it useful in various chemical reactions. It is often employed to convert alcohols into better leaving groups, thereby facilitating nucleophilic substitution reactions. For example, a primary alcohol can be reacted with tosyl chloride in the presence of a base like pyridine to form a tosylate ester. This tosylate ester can then undergo SN2 reactions with nucleophiles. The tosylate anion is stabilized by resonance, which contributes to its effectiveness as a leaving group. It is also used as a counterion in ionic compounds. For instance, it can be paired with positively charged organic cations. Its stability and chemical properties make it a versatile reagent in synthetic organic chemistry.