Reaction Pathway of Conjugate Addition of Lithium Organozincates to s-trans-Enones

摘要

Zinc and copper are neighbors in the periodic table, so that Zn-(Ⅱ) and Cu(Ⅰ) have isoelectronic states, and consequently, their organometallic complexes have many similarities in reactivity. For instance, their ate complexes, lithium triorganozincates R_3Zn(Ⅱ)-Li and lithium diorganocuprates R_2Cu(I)Li, react smoothly and selectively with α, β-unsaturated carbonyl compounds to undergo 1,4-addition reactions, and hence both can be classified as "soft" reagents (Figure 1). However, this similarity is essentially superficial because the group 11 metal is a transition metal element and the group 12 metal belongs to the main group.