Chiral Bicyclo[3.3.0]octa‐2,5‐dienes as Steering Ligands in Substrate‐Dependent Rhodium‐Catalyzed 1,4‐Addition of Arylboronic Acids to Enones

Helbig, Sarah; Sauer, Sven; Cramer, Nicolai; Laschat, Sabine; Baro, Angelika; Frey, Wolfgang

doi:10.1002/adsc.200700232

Cited by 123 publications

(42 citation statements)

References 55 publications

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“…Since the first application of chiral (S,S)-2,5-dibenzylbicyclo[2.2.1]heptadiene ((S,S)-L27b) in the addition of phenylboronic acid to cyclohex-2-enone by Hayashi and coworkers [93], a variety of bicyclic diene scaffolds [94][95][96][97][98][99][100][101][102][103][104] has been successfully applied (Scheme 1.15). Independently, Carriera and coworkers reported the application of a chiral diene for Ir-catalyzed allylic substitution [105].…”

Section: Diene Ligandsmentioning

confidence: 99%

Rhodium‐ and Palladium‐Catalyzed Asymmetric Conjugate Additions

Berthon

Hayashi

2010

Catalytic Asymmetric Conjugate Reactions

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Section: Diene Ligandsmentioning

confidence: 99%

Rhodium‐ and Palladium‐Catalyzed Asymmetric Conjugate Additions

Berthon

Hayashi

2010

Catalytic Asymmetric Conjugate Reactions

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“…To further examine the reactivity of this catalyst, the reaction of different cyclic enones (11) with trifluoroborate salts (14), boronate ester (15), and tetraarylborate salts (16) were studied under the optimal reaction conditions ( Table 3). To our delight, moderate to good yields and enantioselectivities were also obtained by the reaction of cyclic enones with potassium trifluoroborate salts (89À92% yield, 68À94% ee, entries 1À5).…”

Section: Notementioning

confidence: 99%

A Class of Benzene Backbone-Based Olefin–Sulfoxide Ligands for Rh-Catalyzed Enantioselective Addition of Arylboronic Acids to Enones

Xue

Wan

2011

J. Org. Chem.

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b S Supporting Information I n the past few years, significant efforts have been made on the development of the highly efficient chiral ligands in Rhcatalyzed asymmetric 1,4-addition of organoboron reagents, which has rapidly developed into a powerful tool for the stereoselective formation of carbonÀcarbon bonds. 1À6 Pioneered by the groups of Hayashi and Carreira, chiral olefins as a new class of promising ligands have attracted great attention in recent years, 7À9 and many excellent olefin-based ligands such as diene ligands, 10À23 olefinÀphosphine ligands, 24À30 and olefinÀnitrogen ligands 31,32 have been successfully developed in the HayashiÀMiyaura asymmetric reactions. Meanwhile, except for a chiral auxiliary in numerous asymmetric transformations, the application of sulfoxides 33 as ligands, especially the chiral bis-sulfoxides, 34À38 has most recently been appealing in the HayashiÀMiyaura reaction.In view of ready availability, air and moisture stability, and fine chiral environment of sulfoxides, as well as the relatively good coordination ability of alkenes and sulfoxides to transition metals, we envisioned that the combination of alkenes and sulfoxides would allow the advantages of each class to be united which provided good opportunities to find highly efficient hybrid ligands. However, examples on the combination of alkenes with inherent chiral sulfoxides into chiral olefinÀsulfoxide hybrid ligands were very few; 39À43 the sulfoxides were mainly limited to tert-butylsulfinyl groups, and the incorporation of alkenes with different sulfinyl groups was still absent (Figure 1). Herein, we present our efforts on the development of a class of readily available and easily tunable benzene backbone-based olefinÀsulfoxide ligands for the rhodium-catalyzed asymmetric addition reaction.Inspired by recent success of olefinÀoxazoline 32 and bis-sulfoxide 36 ligands based on benzene backbone in asymmetric catalysis, a benzene ring was chosen as an internal ring skeleton to strengthen the coordination ability of alkenes to transition metals. Olefin and sulfoxide frameworks attached to the benzene ring in a 1,2-fashion would be helpful for the coordination of olefins and sulfoxides to transition metals. We reasoned that the combination of η 2 -binding olefins with η 1 -binding sulfoxide would allow new coordination geometries and possibilities in the class of hybrid ligands. Moreover, to further examine the influence of electronic and steric modulations at the olefinÀsulfoxide hybrid ligands on the reactivity and enantioselectivity of the Rh-catalyzed HayashiÀMiyaura reaction, the ligands bearing different sulfinyl moieties were also examined, and thus the highly modular and easily tunable olefinÀsulfoxide ligands were formed (Scheme 1). Subsequently, a series of electronically and sterically varied benzene backbone-based olefinÀsulfoxide ligands (Figure 2) were prepared in a facile two-step synthesis.As an illustrative example, the synthesis of ligand 6c bearing a (R)-tert-butylsulfinyl group was discussed (Schem...

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“…Similar results were observed by Laschat and co-workers in an independent work. 30 In their report, dibenzyl-substituted diene 18g was found to be a better ligand for the 1,4-addition to acyclic enones, affording the highest enantioselectivity (up to 91% ee).…”

Section: Rhodium-catalyzed Asymmetric Addition To Ab-unsaturated Ketmentioning

confidence: 96%

Development of Bicyclo[3.3.0]octadiene- or Dicyclopentadiene-Based Chiral Diene Ligands for Transition-Metal-Catalyzed Reactions

Feng¹,

Xu²,

Lin³

2011

Synlett

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This account summarizes our efforts on the design, synthesis, and application of two classes of chiral diene ligands bearing bicyclo[3.3.0]octadiene or dicyclopentadiene skeletons. These chiral diene ligands can be readily prepared from inexpensive commercial materials with enzymatic resolution as the key synthetic step. The ligands have been successfully applied in some rhodiumcatalyzed reactions, including 1,4-addition to a,b-unsaturated carbonyl compounds, arylation of imines, and conjugate addition to nitroalkenes. In addition, they have been used in the first successful palladium-diene-catalyzed asymmetric reaction.

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Chiral Bicyclo[3.3.0]octa‐2,5‐dienes as Steering Ligands in Substrate‐Dependent Rhodium‐Catalyzed 1,4‐Addition of Arylboronic Acids to Enones

Cited by 123 publications

References 55 publications

Rhodium‐ and Palladium‐Catalyzed Asymmetric Conjugate Additions

Rhodium‐ and Palladium‐Catalyzed Asymmetric Conjugate Additions

A Class of Benzene Backbone-Based Olefin–Sulfoxide Ligands for Rh-Catalyzed Enantioselective Addition of Arylboronic Acids to Enones

Development of Bicyclo[3.3.0]octadiene- or Dicyclopentadiene-Based Chiral Diene Ligands for Transition-Metal-Catalyzed Reactions

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