Download PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... The reagent system CuO·HBF 4 /I 2 /Et 3 SiH generates in situ hydrogen iodide which regioselectively adds to alkenes and alkynes. The mild nature of this system tolerates the presence of different groups on the unsaturated compound. ... Hydrogen iodide, generated in situ from CuO·HBF 4 /I ...