The past few years have witnessed considerable progress in electrophilic chalcogen-catalysis. In this research realm, the selenium-p-acid catalysis, 2 wherein a selenium catalyst chemoselectively activates an alkene or alkyne, is particularly interesting by offering unique reactivities which could be complementary to those of transition metal catalyst 3 (e.g., gold, 4 platinum and palladium 6 complexes). The high carbophilicity of selenium catalyst offers additional advantages such as good functional group tolerance, simplicity of synthetic operation and mild conditions. However, the utility of selenium-p-acid catalysis may be plagued by the intrinsically challenging regioselectivity when nonpolarized internal alkenes are used as reaction partners (Scheme 1a). In a typical reaction manifold, an initial coordination of selenium ion onto olefinic p-bond leads to the formation of a highly electrophilic seleniranium intermediate A. This intermediate could be stereoselectively, but not regioselectively, trapped by a nucleophile to form two sets of selenide adducts (B and C). Depending on the reaction parameters (for examples, substituent on the double bond and the oxidant), both adducts could be potentially converted to either allylic, vinylic or 1,2-difunctionalization product. 1 This was reflected by the seminal work of Sharpless, 7 wherein the use of unsymmetrical internal alkenes produced the unselective chlorination mixtures (Scheme 1b).