Design and Reactivity of Organic Functional Groups — 2-Pyridylsulfonates as Nucleofugal Esters: Remarkably Mild Transformations into HAlides and Olefins

Abstracr -The novel 2-pyridylsulfonate esters are excellent leaving groups for the preparation of bromides and olefins under very mild reaction conditions.Displecementb occur with inversion of configuration.The formation of carbon-halogen bonds from alcohols is a well documented, and fundamentally important reaction in organic chemistry.'Indeed, the chemical literature is abound with detailed mechanistic studies,' as well as preparatively useful example^.^In general, there are two protocols for the formation of halides from primary end secondary alcohols.In the classical approach, an appropriate leaving group (nueleofuge) such as a sulfonste ester is involved.In the second method, a direct conversion from the alcohol can be achieved via the intermediacy of an alkoxyphosphonium halide.'In spite of numerous examples of such halogenations, there is still a need to improve aspects of efficiency, mildneee of reaction conditions and overall compatibility.Continueing our studies on the design, reactivity and nucleofugal character of organic functional ' X / RBr + MgXz, C W I z * (Inversion) OD, few minutes A: X = N , Y = O Br-Mg-B: X = N, Y = lone pair M = Pd, Zn, Fe c X = C , Y = O Chloride