Transmetalation. II. A convenient preparation of vinylic copper(I) species from acetylenes organozirconium intermediates

1,1-Cycloaddition of zirconacyclopentadienes to propynoates

“…It is noteworthy that this is the first example of direct Michael addition of organozirconocene compounds. So far, the Michael addition was observed only after transmetallation of organozirconium compounds to Cu 2,6 or Ni 7 compounds. This demonstrated that a hydrogen (deuterium) atom is indeed transferred from the second propynoate (deuterated propynoate).…”

Transmetalation Reactions Producing Organocopper Reagents

“…Benzylic organomanganese reagents prepared by direct insertion of activated manganese metal display the same behavior (Scheme 2.60) [131]. Excellent results are also obtained for 1,4-additions of organomanganese reagents to unsaturated esters in the presence of CuCl (3 mol%) [127].…”

“…Transmetalation reactions of organozirconium reagents were pioneered by Schwartz [130][131][132], with improved procedures developed more recently by Lipshutz [133] and Wipf [134]. The hydrozirconation of 1-hexene with H(Cl)ZrCp 2 at 25 C under sonication conditions produces the n-hexylzirconium complex 127, which adds to cyclohexenone in the presence of CuBrÁMe 2 S (10 mol%) to afford the desired product 128 in 79% isolated yield (Scheme 2.61) [134].…”

Applications of the β-Azidonation Reaction to Organic Synthesis. α,β-Enones, Conjugate Addition, and γ-Lactam Annulation

“…Unfortunately, the lack of reactivity of the alkenylzirconium derivatives in C−C bond formation have limited their use. Transmetalation chemistry to give a more reactive organometallic species was developed to broaden their reactivity. − Zirconocene complexes have also been used catalytically to control the monocarboalumination and hydroalumination of alkynes . These new organometallic species have been used in conjugate addition reactions to α,β-enones .…”