Catalytic Asymmetric Cross‐Couplings of Racemic α‐Bromoketones with Arylzinc Reagents

Lundin, Pamela M.; Esquivias, Jorge; Fu, Gregory C.

doi:10.1002/ange.200804888

Cited by 54 publications

(11 citation statements)

References 27 publications

(15 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Following the initial disclosures the authors have demonstrated the exceptionally wide scope of the transformation, with efficient couplings of primary and secondary alkyl chlorides, bromides, iodides, carbonates, and sulfonates with alkyl-, vinyl-, and arylzinc nucleophiles (Figure 4). 45,46,47,48,49,50,51,52,53,54 Furthermore, the authors have also developed conditions for enantioselective Suzuki, 55,56,57,58,59,60 Hiyama, 61 Kumada, 62 and zirconium-Negishi 53,63 couplings with a variety of alkyl electrophiles.…”

Section: Stereoablative Transformationsmentioning

confidence: 99%

Advances in Stereoconvergent Catalysis from 2005 to 2015: Transition-Metal-Mediated Stereoablative Reactions, Dynamic Kinetic Resolutions, and Dynamic Kinetic Asymmetric Transformations

et al. 2017

View full text Add to dashboard Cite

An important subset of asymmetric synthesis is dynamic kinetic resolution, dynamic kinetic asymmetric processes and stereoablative transformations. Initially, only enzymes were known to catalyze dynamic kinetic processes but recently various synthetic catalysts have been developed. This review summarizes major advances in non-enzymatic, transition metal promoted dynamic asymmetric transformations reported between 2005 and 2015.

show abstract

Section: Stereoablative Transformationsmentioning

confidence: 99%

Advances in Stereoconvergent Catalysis from 2005 to 2015: Transition-Metal-Mediated Stereoablative Reactions, Dynamic Kinetic Resolutions, and Dynamic Kinetic Asymmetric Transformations

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The difficult issue of cross-coupling with secondary halides [125] having β-hydrogens has been addressed with nickel catalysts. In the presence of NiCl 2 ·glyme and the appropriate enantiopure Pybox ligand (269 or 273), arylzincs can react with racemic propargyl halides [205] or racemic α-bromo-ketones [206] to provide the corresponding coupling products in excellent yields and with good enantioselectivities as shown for 268 and 272 (Scheme 4.60). Note, however, that the electrophiles are somewhat activated.…”

Section: Cross-coupling With C(sp 3 )-Electrophilesmentioning

confidence: 99%

“…Styrenylzinc reagents are also valuable nucleophiles in this crosscoupling reactions, but their stereoselectivity is low. Scheme 4.60 Ni-catalyzed cross-coupling of arylzincs with secondary halides [205,206].…”

Section: Cross-coupling With C(sp 3 )-Electrophilesmentioning

confidence: 99%

Carbon–Carbon Bond Forming Reactions Mediated by Organozinc Reagents

Chemla

Ferreira

Jackowski

et al. 2013

Metal‐Catalyzed Cross‐Coupling Reactions and More

View full text Add to dashboard Cite

“…[8] In an umpolung approach, Fu et al reported asymmetric coupling between a-haloketone electrophiles and arylmetal reagents. [9] Herein, we report the first palladiumcatalyzed coupling of ketones to produce tertiary centers with excellent ee values [Eq. (5)].…”

mentioning

confidence: 99%

Arene CHO Hydrogen Bonding: A Stereocontrolling Tool in Palladium‐Catalyzed Arylation and Vinylation of Ketones

et al. 2013

View full text Add to dashboard Cite

Transition-metal-catalyzed a-arylation of carbonyl compounds has become a very useful tool to prepare aarylcarboxylic acids and derivatives.[1] Many asymmetric couplings have been developed for arylation of ketones, [2] aldehydes, [3] oxindoles [4] and a-methylacetoacetates, [5] etc. For example, in a nickel-catalyzed method reported by Hartwig, enolates were formed in situ from cyclic ketones and a strong base. They coupled efficiently with aryl triflates to form quaternary centers with high ee values [Eq. (1), Scheme 1].[2e]These asymmetric processes cannot be used to construct tertiary centers because arylated products contain acidic aprotons and the latter cannot survive the basic conditions. Thus, arylation of enolates to form tertiary centers must use preformed soft enolates with low basicity.[6] Only recently, MacMillan et al. and Gaunt et al. independently reported arylations of enamines derived from aldehydes as well as silyl enolates of imides to selectively form tertiary centers. [Eq. (2)- (3)].[7] Reactive diaryliodonium reagents must be used and ketone substrates were not reported. In 2011, we realized the first palladium-catalyzed, highly stereoselective arylation of ester enolates for construction of tertiary centers [Eq. (4)].[8] In an umpolung approach, Fu et al. reported asymmetric coupling between a-haloketone electrophiles and arylmetal reagents.[9] Herein, we report the first palladiumcatalyzed coupling of ketones to produce tertiary centers with excellent ee values [Eq. (5)].At first, we attempted to couple a silyl enolate of 1-tetralone using our ester coupling procedure (2 mol % Pd/ ligand L and LiOAc in PhCF 3 ). However, no product was formed in the presence of LiOAc. With CsF, arylation occurred, but the product racemized. To our delight, we finally found that the tin enolate of 1-tetralone can couple very efficiently with 91 % ee when L1 was used. No erosion of the ee value was observed over time. The tin enolate was formed easily by stirring alkenyl acetate with nBu 3 Sn(OMe) at room temperature, and it was used directly without purification. [10] During catalyst discovery, the Pd(OAc) 2 /difluorphos catalyst, which was previously used by Hartwig et al., [2e] gave poor results with 38 % ee. [Ni(cod) 2 ]/difluorphos (cod = cyclo-1,5-octadiene) was catalytically inactive.[2d] Pd/MOP showed low activity and gave moderate ee values (Scheme 2). We then modified MOP by installing the more donating PCy 2 group and O-2-naphthyl side chain. The resulting L1 turned out to be both active and selective. Structural analogues carrying Scheme 1. Examples of asymmetric coupling of enolates. Tf = trifluoromethanesulfonyl, TMS = trimethylsilyl.

show abstract

Catalytic Asymmetric Cross‐Couplings of Racemic α‐Bromoketones with Arylzinc Reagents

Cited by 54 publications

References 27 publications

Advances in Stereoconvergent Catalysis from 2005 to 2015: Transition-Metal-Mediated Stereoablative Reactions, Dynamic Kinetic Resolutions, and Dynamic Kinetic Asymmetric Transformations

Advances in Stereoconvergent Catalysis from 2005 to 2015: Transition-Metal-Mediated Stereoablative Reactions, Dynamic Kinetic Resolutions, and Dynamic Kinetic Asymmetric Transformations

Carbon–Carbon Bond Forming Reactions Mediated by Organozinc Reagents

Arene CHO Hydrogen Bonding: A Stereocontrolling Tool in Palladium‐Catalyzed Arylation and Vinylation of Ketones

Contact Info

Product

Resources

About