Recent Advances in Metal-Catalyzed Asymmetric Conjugate Additions

Abstract

The conjugate addition of carbon nucleophiles to acceptor activated olefins is one of the most important reactions for carbon-carbon bond formation. With optically active metal complexes this transformation can be catalyzed enantioselectively. This review is a collection of the newer literature (since 2001) on this topic. The metal salts and complexes applied are in a broad range, starting from solely Lewis acidic M(II) and M(III) compounds, such as magnesium, zinc, boron, aluminum and the lanthanoids. Transitionmetal catalysts suitable for asymmetric conjugate additions are compounds of ruthenium, iridium, nickel, and palladium. The most flourishing fields are, however, the catalysis with rhodium and copper complexes. Rhodium catalysts often have a chiral diphosphane like BINAP, or an optically active olefin as the ligand, the latter being a newer development. The privileged ligand structures for copper catalysts are monodentate phosphoramidites with axially chiral BINOL or other biphenol units.

Chiral Amidophosphane-Rhodium(I)-Catalyzed Asymmetric Conjugate Arylation of Acyclic Enones with Arylboronic Acids

“…Other bases, potassium phosphate and triethylamine, also gave the similar level of efficiency (entries 5,6). N-Boc-L-valine-connected amidophosphane 9 was not a better ligand than 1 to give 8aa with 63% ee (entry 7).…”

“…[1][2][3][4][5] Tremendous efforts on the discovery of efficient chiral sources for the reaction with carbon-and hetero-nucleophiles provided a fruit of chiral sources like phosphorous compounds.6) A touchstone for the evaluation of chiral sources has been the asymmetric reaction of cyclohexenone 2 with diorganozinc-copper(I), 7,8) Grignard reagent-copper(I) 9,10) or arylboronic acid-rhodium(I) [11][12][13][14][15][16][17][18] reagent-catalyst combinations. We have also engaged in this fascinating challenge and fortunately succeeded in the development of chiral amidophosphane 1-based catalytic asymmetric conjugate addition reaction of 2 with organometallic reagents, especially, Grignard reagents [19][20][21] and diorganozincs.…”

“…[1][2][3][4][5] Tremendous efforts on the discovery of efficient chiral sources for the reaction with carbon-and hetero-nucleophiles provided a fruit of chiral sources like phosphorous compounds.…”

Phosphine-catalyzed asymmetric additions of malonate esters to γ-substituted allenoates and allenamides

“…allene | catalysis T here are a variety of powerful methods for functionalizing carbonyl compounds in the α-and the β-positions, including classic approaches such as reacting enolates with electrophiles and adding nucleophiles to α,β-unsaturated carbonyl compounds (1,2). In contrast, there are few general processes for incorporating new substituents in the γ-position of carbonyl compounds, particularly catalytic asymmetric reactions that form carboncarbon bonds (3).…”

“…contributed equally to this work. 2 To whom correspondence should be addressed. E-mail: gcf@mit.edu.…”