A Convenient and Genuine Equivalent to HZrCp2Cl Generated in Situ from ZrCp2Cl2−DIBAL-H

reaction: see text Slow addition of 1 equiv of (i)Bu2AlH to ZrCp2Cl2 in THF provides a convenient route to either HZrCp2Cl-(i)Bu2AlCl (Reagent I) or HZrCp2Cl (Reagents II and III). The latter represents a highly convenient route to genuine HZrCp2Cl, while Reagent I is useful for regio- and stereoselective conversion of 1- and 2-alkynes into (E)-1-iodo-1-alkenes and (E)-2-iodo-2-alkenes, respectively.