Asymmetric allylic alkylations (AAAs) are among the most powerful C-C bond-forming reactions. We present a brief overview of copper-catalyzed AAAs with organometallic reagents and discuss our own contributions to this field. Work with zinc reagents and phosphoramidite ligands provided a framework for later developments which employ Grignard reagents and ferrocenyl ligands. High yields and excellent regioselectivities and enantioselectivities are achieved. The AAAs may be more general than previously envisioned, in terms of using substrates functionalized with heteroatoms at various positions; heteroatom substituents at the γ-position provide densely functionalized building blocks. These h-AAA reactions rely on the design of appropriate substrates containing heteroatoms and have allowed us to demonstrate viable new approaches toward the synthesis of versatile organic building blocks. We illustrate that the chiral secondary allylic alcohols, primary homo-allylic alcohols and amines can readily be obtained in high enantiomeric purity in a catalytic asymmetric fashion by copper-catalyzed AAAs. Furthermore, we show that manipulation of the terminal olefin provides chiral building blocks where the ee of the starting materials is preserved.
F. Lopez, A. J. Minnaard, B. L. Feringa. In Catalytic Asymmetric Conjugate Addition and Allylic Alkylation Reactions using Grignard Reagents, S. Rappoport, J. Marek (Eds.), The Chemistry of Organomagnesium Compounds, Wiley-VCH, New York (in press).
F. Lopez, B. L. Feringa. In Catalytic Asymmetric Conjugate Addition Reactions of Organometallic Reagents, M. Christmann, S. Brase (Eds.), p. 78, Asymmetric Synthesis: The Essentials, Wiley-VCH, New York (2007).
, A. Alexakis, C. Malan, L. Lea, K. Tissot-Croset, D. Polet, C. Falciola. Chimia 60, 124 (2006).
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