Enantiospecific and Regioselective Rhodium-Catalyzed Allylic Alkylation:  Diastereoselective Approach to Quaternary Carbon Stereogenic Centers

and, P. Andrew Evans; Kennedy, Lawrence J.

doi:10.1021/ol005953g

Cited by 67 publications

(17 citation statements)

References 13 publications

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“…For example, the application of this reaction to a range of enantiomerically enriched allylic carbonates with the sodium salt of methyl phenylsulfonylacetate provides products that represent important synthons for targetdirected synthesis (Tab. 10.1) [17].…”

Section: Rhodium-catalyzed Allylic Alkylation Reaction With Stabilizementioning

confidence: 98%

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Rhodium(I)‐Catalyzed Allylic Substitution Reactions and Their Applications to Target Directed Synthesis

Leahy

Evans

2005

Modern Rhodium‐Catalyzed Organic Reactions

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IntroductionThe drive for the development of more cost-effective, expeditious, and environmentally benign synthetic transformations for the production of fine chemicals, pharmaceuticals, and agrochemicals provides the impetus for the development of new catalytic processes. The allylic substitution reaction represents a powerful synthetic transformation that has been extensively studied using a wide range of transition metal complexes [1][2][3]. The enantioselective metal-catalyzed reaction manifold is particularly pertinent; however, the major limitation with this transformation is the necessity to employ substrates that furnish symmetrical p-allyl intermediates, to circumvent problems associated with regiochemical infidelity. Although there are reports of regio-and enantioselective allylic alkylation with acyclic 3-substituted propenyl derivatives, useful selectivity is, for the most part, limited to electronically biased cinnamyl derivatives [4]. Furthermore, the alkylation of unsymmetrical chiral nonracemic allylic alcohols generally leads to considerable racemization through p-r-p isomerization due to the fluxional or rapidly equilibrating nature of p-allyl intermediates [5]. Hence, although these reactions were previously unselective with other transition metal catalysts, they may be accomplished with unparalleled selectivity using rhodium catalysts. This chapter outlines some of the most recent advances in the area of rhodium-catalyzed allylic substitution reactions. Regioselective Rhodium-Catalyzed Allylic AlkylationBy 1984, the palladium-catalyzed allylic alkylation reaction had been extensively studied as a method for carbon-carbon bond formation, whereas the synthetic utility of other metal catalysts was largely unexplored [1,2]. Hence, prior to this period rhodium's ability to catalyze this transformation was cited in only a single reference, which described it as being poor by comparison with the analogous palladium-catalyzed version [6]. Nonetheless, Yamamoto and Tsuji independently described the first rhodium-catalyzed decarboxylation of allylic phenyl carbonates and the intramolecular decarboxylative allylation of allyl b-keto carboxylates respectively [7,8]. These findings undoubtedly laid the groundwork for Tsuji's seminal work on the regiospecific rho-

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Section: Rhodium-catalyzed Allylic Alkylation Reaction With Stabilizementioning

confidence: 98%

“…(17) 90(13)84 (45) 86 (26) 95 95 95 95 80 75 70 70 a) Numbers in parenthesis refer to % ee. b) One equivalent.…”

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confidence: 99%

Rhodium(I)‐Catalyzed Allylic Substitution Reactions and Their Applications to Target Directed Synthesis

Leahy

Evans

2005

Modern Rhodium‐Catalyzed Organic Reactions

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“…Rh-catalysed allylic substitutions have unique features and can be highly regioselective 12 . Evans and co-workers reported that alkylations with stabilized nucleophiles 13,14 and arylations with non-stabilized aryl zinc nucleophiles 15 are highly stereospecific processes-overall retention of configuration is observed with stabilized nucleophiles and overall inversion occurs with arylzinc compounds, so that highly enantiomerically enriched compounds can be obtained by starting from single-enantiomer allylic coupling partners (Fig. 1c).…”

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Rhodium-catalysed asymmetric allylic arylation of racemic halides with arylboronic acids

Sidera

Fletcher

2015

Nature Chem

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Csp(2)-Csp(2) cross-coupling reactions between arylboronic acid and aryl halides are widely used in both academia and industry and are strategically important in the development of new agrochemicals and pharmaceuticals. Csp(2)-Csp(3) cross-coupling reactions have been developed, but enantioselective variations are rare and simply retaining the stereochemistry is a problem. Here we report a highly enantioselective Csp(2)-Csp(3) bond-forming method that couples arylboronic acids to racemic allyl chlorides. Both enantiomers of a cyclic chloride are converted into a single enantiomer of product via a dynamic kinetic asymmetric transformation. This Rh-catalysed method uses readily available and inexpensive building blocks and is mild and broadly applicable. For electron-deficient, electron-rich or ortho-substituted boronic acids better results are obtained with racemic allyl bromides. Oxygen substitution in the allyl halide is tolerated and the products can be functionalized to provide diverse building blocks. The approach fills a significant gap in the methods for catalytic asymmetric synthesis.

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“…Nach oxidativer Addition des Allylfragments an den Katalysator wird, insbesondere bei der palladiumkatalysierten Variante, ein h 3 -Allylfragment als reaktives Intermediat angenommen, das h 3 -h 1 -h 3 -Umlagerungsreaktionen eingeht. [2] Rhodium- [3][4][5][6] und eisenkatalysierte allylische Alkylierungen [7] sind von großem Interesse, da in vielen Fällen das ipso-Substitutionsprodukt als Hauptisomer erhalten wurde. Eine mögliche Erklärung für diese Regioselektivität und die Übertragung der Enantioselektivität würde ein s-Allylintermediat mit schwacher p-Koordination liefern (Schema 1 oben).…”

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Erste Röntgenstrukturanalysen von Rhodium(III)‐η¹‐Allyl‐Komplexen und ein plausibler Mechanismus für allylische Isomerisierungsreaktionen

et al. 2009

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Allyltransfer von Metall zu Metall: Anhand der ersten strukturell charakterisierten Rh(η1‐allyl)‐Komplexe wird gezeigt, dass der σ‐gebundene Allylsubstituent von einem RhIII‐ auf einen RhI‐Komplex im schnellen Gleichgewicht übertragen werden kann. Dies könnte die Abnahme der Regioselektivität in Rh‐katalysierten allylischen Alkylierungen erklären, für die Komplex 1 ein aktiver Katalysator ist.

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Enantiospecific and Regioselective Rhodium-Catalyzed Allylic Alkylation: Diastereoselective Approach to Quaternary Carbon Stereogenic Centers

Cited by 67 publications

References 13 publications

Rhodium(I)‐Catalyzed Allylic Substitution Reactions and Their Applications to Target Directed Synthesis

Rhodium(I)‐Catalyzed Allylic Substitution Reactions and Their Applications to Target Directed Synthesis

Rhodium-catalysed asymmetric allylic arylation of racemic halides with arylboronic acids

Erste Röntgenstrukturanalysen von Rhodium(III)‐η¹‐Allyl‐Komplexen und ein plausibler Mechanismus für allylische Isomerisierungsreaktionen

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Enantiospecific and Regioselective Rhodium-Catalyzed Allylic Alkylation: Diastereoselective Approach to Quaternary Carbon Stereogenic Centers

Cited by 67 publications

References 13 publications

Rhodium(I)‐Catalyzed Allylic Substitution Reactions and Their Applications to Target Directed Synthesis

Rhodium(I)‐Catalyzed Allylic Substitution Reactions and Their Applications to Target Directed Synthesis

Rhodium-catalysed asymmetric allylic arylation of racemic halides with arylboronic acids

Erste Röntgenstrukturanalysen von Rhodium(III)‐η1‐Allyl‐Komplexen und ein plausibler Mechanismus für allylische Isomerisierungsreaktionen

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Erste Röntgenstrukturanalysen von Rhodium(III)‐η¹‐Allyl‐Komplexen und ein plausibler Mechanismus für allylische Isomerisierungsreaktionen