Enantiospecific sp2–sp3 coupling of secondary and tertiary boronic esters

Bonet, Amadeu; Odachowski, Marcin; Leonori, Daniele; Essafi, Stéphanie; Aggarwal, Varinder K.

doi:10.1038/nchem.1971

Cited by 382 publications

(239 citation statements)

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“…By exploiting the propensity of organoboronates to undergo stereospecific 1,2-metallate rearrangements,t he chiral secondary boronic ester [15] in 2awas subjected to an oxidative C(sp 2 ) À C(sp 3 )cross-coupling with furyllithium, under conditions recently described by the group of Aggarwal, [16] delivering the cross-coupled product 4 with preserved stereochemical integrity (Scheme 4b). It should be noted that this transformation would be difficult to achieve in the corresponding b-boron-substituted carbonyl derivatives owing to the reactivity of ac arbonyl group towards organolithium reagents.…”

Section: Methodsmentioning

confidence: 99%

Catalytic Asymmetric Synthesis of Phosphine Boronates

et al. 2015

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The first catalytic enantioselective synthesis of ambiphilic phosphine boronate esters is presented. The asymmetric boration of a,b-unsaturated phosphine oxides catalyzedbyacopper bisphosphine complex affords optically active organoboronate esters that bear av icinal phosphine oxide group in good yields and high enantiomeric excess.The synthetic utility of the products is demonstrated through stereospecific transformations into multifunctional optically active compounds.Chiral organophosphorus compounds play aprominent role in many areas,i ncluding organometallic chemistry,c hemical biology,a nd the production of pharmaceuticals or agrochemicals.[1] In homogeneous catalysis,c hiral phosphines are essential in the field of asymmetric catalysis as we take advantage of their ability to serve as ancillary ligands with tunable steric and electronic properties.[2] More recent applications in the rapidly emerging field of frustrated Lewis pair (FLP) chemistry have led to new catalytic systems for small-molecule activation.[3] In particular, phosphinesubstituted borane and boronate esters have gained increasing interest for their applications in intramolecular FLP chemistry [4] and as organocatalysts or ligands in metalcatalyzed transformations.[5] In these systems,t he boron atom also has the ability to bind transition metals by acting as a s-acceptor ligand, offering new fascinating possibilities in terms of controlling reactivity.[6] Furthermore,t he boronate group enables av ariety of transformations by virtue of its ability to undergo stereospecific transformations to form CÀO, CÀN, or CÀCbonds. [7] Despite the promising reactivity of these compounds,acatalytic asymmetric method to readily access phosphine-substituted chiral boronates has not been described, and to the best of our knowledge,o nly al imited range of these chiral structures have been explored because of al ack of methods for their synthesis (Scheme 1a). [8] Important procedures for the asymmetric synthesis of chiral organoboranes are transition-metal-and organocatalyzed additions of diboron reagents,s uch as bis(pinacolato)-diboron, to electron-deficient alkenes. [9] In particular,the use of copper catalysts [10] has been highly successful, and avariety of cyclic or acyclic chiral b-boron-substituted carbonyl derivatives can now be obtained with excellent levels of enantiopurity.W eq uestioned whether ar elated process involving the copper-catalyzed conjugate boration of alkenyl phosphine oxides could be developed despite the fact that the use of these substrates in catalytic asymmetric conjugate additions (ACAs) with organometallic reagents has remained am ajor challenge to date.[11] Thec orresponding enantiomerically enriched vicinal phosphine oxide boronates could then also be derivatized through stepwise stereospecific transformations at both the boron and phosphorus functional groups.Herein, we report an efficient catalytic method using achiral copper(I) complex to produce optically active vicinal ambiphilic phosphine oxide boronates wi...

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Section: Methodsmentioning

confidence: 99%

Catalytic Asymmetric Synthesis of Phosphine Boronates

et al. 2015

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“…[ 11] We recognized that as imilar mechanism could be accessible with pyridines, but that the dearomatized intermediates might be isolable. Thus,acylation of boronate 4 could prompt a1,2-migration to form an ew C À Cb ond (Scheme 1d).…”

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Synthesis and Utility of Dihydropyridine Boronic Esters

et al. 2015

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“…furan, thiophene, indole, and benzofuran) and electron‐rich aromatics, provided they were substituted with donor groups at the meta ‐position. The meta donor group and the electron‐rich boronate worked synergistically to promote an electrophilic reaction on the aromatic ring 5a,5b. Positioning the donor group in the para ‐position pushes electron density onto the sp 3 carbon atom of the boronate complex, resulting in a selective reaction via an S E 2 pathway, rather than an S E Ar pathway (e.g.…”

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Enantiospecific sp²–sp³ Coupling of ortho‐ and para‐Phenols with Secondary and Tertiary Boronic Esters

et al. 2017

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The coupling of ortho‐ and para‐phenols with secondary and tertiary boronic esters has been explored. In the case of para‐substituted phenols, after reaction of a dilithio phenolate species with a boronic ester, treatment with Ph3BiF2 or Martin's sulfurane gave the coupled product with complete enantiospecificity. The methodology was applied to the synthesis of the broad spectrum antibacterial natural product (−)‐4‐(1,5‐dimethylhex‐4‐enyl)‐2‐methyl phenol. For ortho‐substituted phenols, initial incorporation of a benzotriazole on the phenol oxygen atom was required. Subsequent ortho‐lithiation and borylation gave the coupled product, again with complete stereospecificity.

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Enantiospecific sp2–sp3 coupling of secondary and tertiary boronic esters

Abstract: The Suzuki-Miyaura cross-coupling reaction is one of the most widely used reactions in synthesis.

Cited by 382 publications

References 56 publications

Catalytic Asymmetric Synthesis of Phosphine Boronates

Catalytic Asymmetric Synthesis of Phosphine Boronates

Synthesis and Utility of Dihydropyridine Boronic Esters

Enantiospecific sp²–sp³ Coupling of ortho‐ and para‐Phenols with Secondary and Tertiary Boronic Esters

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Enantiospecific sp2–sp3 coupling of secondary and tertiary boronic esters

Abstract: The Suzuki-Miyaura cross-coupling reaction is one of the most widely used reactions in synthesis.

Cited by 382 publications

References 56 publications

Catalytic Asymmetric Synthesis of Phosphine Boronates

Catalytic Asymmetric Synthesis of Phosphine Boronates

Synthesis and Utility of Dihydropyridine Boronic Esters

Enantiospecific sp2–sp3 Coupling of ortho‐ and para‐Phenols with Secondary and Tertiary Boronic Esters

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Product

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Enantiospecific sp²–sp³ Coupling of ortho‐ and para‐Phenols with Secondary and Tertiary Boronic Esters