## 3 Oxylabogenation of Hydrocarbons
### Alkynes as Substrates  
Similarly to the alkene systems mentioned above, I\({}_{2}\)- and IBX-based oxyiodination of aromatics was also applied to alkynes in water (Scheme 60) [155]. The protocol showed good tolerance towards electron-donating and electron-withdrawing substitutions on the aromatic alkynes. The role of IBX is to facilitate the initial addition step of I\({}^{+}\) and water to alkyne, most likely to generate the I\({}^{+}\) active species from I\({}_{2}\). Afterwards, the formed iodo-enol compound would tautomerise to the iodoketone form, affording the target compound. [PERSON] and co-workers described an alternative I\({}_{2}\)-based oxyhalogenation protocol which generated 11 \(\alpha\)-chloroketones in good yields (69-79%) upon the addition of HCl to the corresponding phenylacetylene derivatives in DMSO [156]. The protocol tolerated the presence of electron-withdrawing (i.e., F, Br, Cl, CF\({}_{3}\)) and -donating (i.e., Me, \(n\)-Bu) aromatic substituents. Interestingly, the presence of steric bulk near the alkyne centre (ortho-substitution of the aromatic ring) did not affect its efficacy. Acid-sensitive substrates were not tolerated under these conditions, thus limiting the reaction scope. [PERSON] and co-workers reported the oxybromination of aromatic alkynes mediated by a TsNBr\({}_{2}\) and Na\({}_{2}\)SO\({}_{3}\) system (Table 4) [147]. A broad scope of substrates were efficiently transformed into the desired products, with exclusive formation of the \(\alpha\)-bromoketone observed. Nonetheless, the long reaction times and the use of the non-commercially available TsNBr\({}_{2}\) could be a major hindrance for its widespread application. He and co-workers investigated the same reaction using a commercially available halogenating reagent, 1,3-dibromo-5,5-dimethyldantoin (DBDMH) (Table 4) [157]. The authors illustrated this route's versatility as it yielded \(\alpha\)-bromo-, \(\alpha\)-chloro- and \(\alpha\)-iodoketones without the need to alter the reaction conditions (this was achieved simply by changing the halogenating reagent, 1,3-dihalo-5,5-dimethyldantoin). [PERSON] and others established a route involving the addition of Br\({}_{2}\) to phenylacetylene in cyclodextrin (CD) [158]. An alkyne-CD complex was formed upon the interaction of the substrate in the cavity of the cyclodextrin molecule. The experimental data showed that formation of 2-bromo-1-phenylethanone is enhanced with increased cavity size. In \(\alpha\)-CD (6 glucose units), only 13% of the ketone was observed, whereas in \(\gamma\)-CD (8 glucose units), the GC yield of the ketone increased to 46%. This route stands out as it is the first to demonstrate such a complexation effect on the selectivity of oxyhalogenation reaction. A gold-based oxidative halogenation method was designed by [PERSON] and [PERSON] using [Au(NTf\({}_{2}\))(IPr)] as a catalyst, 8-methylquinoline \(N\)-oxide as the oxidant and methanesulfonic acid (MsOH) [159]. One \(\alpha\)-chloroketone and two \(\alpha\)-bromoketones were obtained via the halide abstraction of the solvent (i.e., dichloro- or dibromoethane). The results, illustrated in Scheme 61, show the poor catalytic activity of the selected Au\({}^{\text{I}}\) complex in this transformation. In 2017, [PERSON] and co-workers demonstrated a Au\({}^{\text{III}}\) system accommodating the oxyhalogenation of terminal alkynes (Scheme 62) [160]. This route yielded aromatic, aliphatic and heteroaromatic \(\alpha\)-bromoketones (15 in total) in good to excellent yields (73-91%). The versatility of this route was further highlighted as it also generated five \(\alpha\)-chloroketones in good to excellent yields (75-90%) and two \(\alpha\)-iodoketones in good yields (81-85%). Although this route seemed to be promising, it brings a number of limitations as the use of silver salts imposed several drawbacks; their limited air- and light-stability, as well as the known interference of Ag in the Au\({}^{\text{I}}\) catalysis [161].