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Among the myriad uses of silicon in organic synthesis, 1 the dimethylphenylsilyl moiety occupies a special niche, perhaps most notably in its service as a hydroxyl group surrogate. 2 Introduction of this moiety is commonly effected via a silyl cuprate reagent, such as that formed from CuCN and 2 equiv of PhMe 2 SiLi (i.e., "(PhMe 2 Si) 2 Cu(CN)Li 2 "). 3 This species, now in its second decade of usage, requires not only 2 equiv of silyllithium but, more importantly, stoichiometric amounts of copper which detract from its appeal, in particular for large-scale reactions. We now report a solution to these issues which allows for consumption of only one silyl group, is applicable to highly hindered substrates, and relies on catalytic amounts of Cu(I). In addition, we disclose the unprecedented use of a rare earth as a new catalyst for accelerating 1,4-additions of an in situ derived silylcuprate.Addition of a toluene solution of Me 2 Zn to preformed PhMe 2 -SiLi in THF at -78 °C generates known PhMe 2 SiZnMe 2 Li. 4

A direct catalytic asymmetric aldol reaction of methyl vinyl ketone is described using our dinuclear zinc catalyst. The obtained aldol adduct functions as a bifunctional building block by utilization of the vinyl functionality. For example, convergent fragment coupling methods have been demonstrated via highly diastereoselective cycloaddition of nitrile oxide after reduction into 1,3-diol or via cross-metathesis reaction.

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