Configurationally stable, enantioenriched organometallic nucleophiles in stereospecific Pd-catalyzed cross-coupling reactions: an alternative approach to asymmetric synthesis

Derosa, Joseph; Biscoe, Mark R.

doi:10.1039/c5sc01710f

Cited by 103 publications

(51 citation statements)

References 70 publications

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“…Via stereospecific, palladium-catalyzed cross couplings with aryl chlorides, trifluoroborate 7 can be converted to a number of highly enantioenriched products with tertiary benzylic stereocenters. 17 …”

Section: Resultsmentioning

confidence: 99%

Accessing Both Retention and Inversion Pathways in Stereospecific, Nickel-Catalyzed Miyaura Borylations of Allylic Pivalates

et al. 2016

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We have developed a stereospecific, nickel-catalyzed Miyaura borylation of allylic pivalates, which delivers highly enantioenriched α-stereogenic γ-aryl allylboronates with good yields and regioselectivities. Our complementary sets of conditions enable access to either enantiomer of allylboronate product from a single enantiomer of readily prepared allylic pivalate substrate. Excellent functional group tolerance, yields, regioselectivities, and stereochemical fidelities are observed. The stereochemical switch from stereoretention to stereoinversion largely depends upon solvent, and can be explained by competitive pathways for the oxidative addition step. Our mechanistic investigations support a stereoretentive pathway stemming from a directed oxidative addition and a stereoinvertive pathway that is dominant when MeCN blocks coordination of the directing group by binding the nickel catalyst.

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Section: Resultsmentioning

confidence: 99%

Accessing Both Retention and Inversion Pathways in Stereospecific, Nickel-Catalyzed Miyaura Borylations of Allylic Pivalates

et al. 2016

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“…Despite these advances,t he stereochemical outcome of the activation of aC À Hbond of atertiary stereogenic center has not been studied because of the challenging formation of tertiary alkyl metal species.H owever, some alkyl transition metal intermediates are configurationally stable and give enantiomerically enriched products,t hus suggesting the possibility of preserving the stereochemistry of at ertiary stereogenic center in transition-metal-catalyzed C À Ha ctivation. [190] Thee ffect of ap re-existing stereogenic center on the stereochemical outcome of metal-catalyzed C(sp 3 )ÀHactivation has been studied. Ahigh level of diastereomeric control has been observed in some reactions of palladium-catalyzed C À Hactivation.…”

Section: Transition-metal-catalyzed Càha Ctivationmentioning

confidence: 99%

Complementary Strategies for Directed C(sp³)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

2017

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The functionalization of C(sp3)−H bonds streamlines chemical synthesis by allowing the use of simple molecules and providing novel synthetic disconnections. Intensive recent efforts in the development of new reactions based on C−H functionalization have led to its wider adoption across a range of research areas. This Review discusses the strengths and weaknesses of three main approaches: transition‐metal‐catalyzed C−H activation, 1,n‐hydrogen atom transfer, and transition‐metal‐catalyzed carbene/nitrene transfer, for the directed functionalization of unactivated C(sp3)−H bonds. For each strategy, the scope, the reactivity of different C−H bonds, the position of the reacting C−H bonds relative to the directing group, and stereochemical outcomes are illustrated with examples in the literature. The aim of this Review is to provide guidance for the use of C−H functionalization reactions and inspire future research in this area.

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“… 3 , 4 However, such a coupling reaction has proved challenging. 5 , 6 This is because the desirable features of the high configurational stability of the C–B bond that enables boronic esters to be isolated and purified also renders them relatively unreactive, and further activation is required in order to engage them in the key transmetalation step of the catalytic cycle. 7 , 8 Furthermore, competing β-hydride elimination can also occur from the aliphatic organo-Pd(II) species, which can have an impact on both yield and stereoselectivity.…”

Section: Introductionmentioning

confidence: 99%

“…Despite these inherent difficulties, examples of Pd-catalyzed sp 2 –sp 3 cross-coupling of chiral organoborons have been reported ( Scheme 2 ). 5 , 6 , 9 − 20 Pioneering work by Crudden showed that benzylic pinacol boronic esters and dibenzylic neopentyl boronic esters could be coupled with high stereospecificity with retention of configuration with aryl iodides. 21 − 23 Liao found that the stereospecific coupling of dibenzylic organoborons could be rendered invertive using the potassium trifluoroborate salt in place of the neopentyl boronic ester, which occurred with retention.…”

Section: Introductionmentioning

confidence: 99%

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Development of Enantiospecific Coupling of Secondary and Tertiary Boronic Esters with Aromatic Compounds

et al. 2016

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The stereospecific cross-coupling of secondary boronic esters with sp2 electrophiles (Suzuki–Miyaura reaction) is a long-standing problem in synthesis, but progress has been achieved in specific cases using palladium catalysis. However, related couplings with tertiary boronic esters are not currently achievable. To address this general problem, we have focused on an alternative method exploiting the reactivity of a boronate complex formed between an aryl lithium and a boronic ester. We reasoned that subsequent addition of an oxidant or an electrophile would remove an electron from the aromatic ring or react in a Friedel–Crafts-type manner, respectively, generating a cationic species, which would trigger 1,2-migration of the boron substituent, creating the new C–C bond. Elimination (preceded by further oxidation in the former case) would result in rearomatization giving the coupled product stereospecifically. Initial work was examined with 2-furyllithium. Although the oxidants tested were unsuccessful, electrophiles, particularly NBS, enabled the coupling reaction to occur in good yield with a broad range of secondary and tertiary boronic esters, bearing different steric demands and functional groups (esters, azides, nitriles, alcohols, and ethers). The reaction also worked well with other electron-rich heteroaromatics and 6-membered ring aromatics provided they had donor groups in the meta position. Conditions were also found under which the B(pin)- moiety could be retained in the product, ortho to the boron substituent. This protocol, which created a new C(sp2)–C(sp3) and an adjacent C–B bond, was again applicable to a range of secondary and tertiary boronic esters. In all cases, the coupling reaction occurred with complete stereospecificity. Computational studies verified the competing processes involved and were in close agreement with the experimental observations.

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Configurationally stable, enantioenriched organometallic nucleophiles in stereospecific Pd-catalyzed cross-coupling reactions: an alternative approach to asymmetric synthesis

Abstract: Several research groups have recently developed methods to employ configurationally stable, enantioenriched organometallic nucleophiles in stereospecific Pd-catalyzed cross-coupling reactions.

Cited by 103 publications

References 70 publications

Accessing Both Retention and Inversion Pathways in Stereospecific, Nickel-Catalyzed Miyaura Borylations of Allylic Pivalates

Accessing Both Retention and Inversion Pathways in Stereospecific, Nickel-Catalyzed Miyaura Borylations of Allylic Pivalates

Complementary Strategies for Directed C(sp³)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

Development of Enantiospecific Coupling of Secondary and Tertiary Boronic Esters with Aromatic Compounds

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Configurationally stable, enantioenriched organometallic nucleophiles in stereospecific Pd-catalyzed cross-coupling reactions: an alternative approach to asymmetric synthesis

Abstract: Several research groups have recently developed methods to employ configurationally stable, enantioenriched organometallic nucleophiles in stereospecific Pd-catalyzed cross-coupling reactions.

Cited by 103 publications

References 70 publications

Accessing Both Retention and Inversion Pathways in Stereospecific, Nickel-Catalyzed Miyaura Borylations of Allylic Pivalates

Accessing Both Retention and Inversion Pathways in Stereospecific, Nickel-Catalyzed Miyaura Borylations of Allylic Pivalates

Complementary Strategies for Directed C(sp3)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

Development of Enantiospecific Coupling of Secondary and Tertiary Boronic Esters with Aromatic Compounds

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Complementary Strategies for Directed C(sp³)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer