Recent advances in asymmetric borylation by transition metal catalysis

Chemical Society Reviews, Journal Year: 2021, Volume and Issue: 50(23), P. 13129 - 13188

Published: Jan. 1, 2021

We provide a comprehensive overview of transition metal-catalysed asymmetric borylation processes to construct C–B, C–C, and other C–heteroatom bonds with considerable attention devoted the reaction modes mechanisms involved.

Language: Английский

---

Stereodivergent Synthesis of Tertiary Fluoride-Tethered Allenes via Copper and Palladium Dual Catalysis

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(19), P. 7285 - 7291

Published: May 10, 2021

Herein we describe a protocol for the unprecedented stereodivergent synthesis of tertiary fluoride-tethered allenes bearing stereogenic center and axis via Cu/Pd synergistic catalysis. A broad scope conjugated enynes are coupled with various α-fluoroesters in high yields diastereoselectivities generally >99% ee. In addition, four stereoisomers allene products ensure precise access to corresponding fluorinated hydrofurans novel axial-to-central chirality transfer process.

Language: Английский

---

Enantio- and Diastereodivergent Construction of 1,3-Nonadjacent Stereocenters Bearing Axial and Central Chirality through Synergistic Pd/Cu Catalysis

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(32), P. 12622 - 12632

Published: Aug. 5, 2021

In contrast to the widely explored methods for asymmetric synthesis of molecules bearing a single stereocenter or adjacent stereocenters, concurrent construction 1,3-stereogenic centers in an enantio- and diastereoselective manner remains challenge, especially acyclic systems. Herein, we report diastereodivergent 1,3-nonadjacent stereocenters allenyl axial central chirality through synergistic Pd/Cu-catalyzed dynamic kinetic allenylation with racemic allenylic esters. The protocol is suitable wide range substrates including challenging esters less sterically bulky substituents provided chiral products high levels diastereoselectivities (up >20:1 dr >99% ee). Furthermore, several representative transformations involving axial-to-central transfer were conducted, affording useful structural motifs containing nonadjacent manner.

Language: Английский

---

Transition-Metal-Catalyzed Functionalization of Alkynes with Organoboron Reagents: New Trends, Mechanistic Insights, and Applications

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(12), P. 7513 - 7551

Published: June 9, 2021

Catalytic functionalization of alkynes with organoboron reagents provides a straightforward access to stereochemically defined multisubstituted alkenes, which are structural motifs commonly found in bioactive compounds and organic materials. Recent progress has substantially broadened the scope this field on several fronts. Strategies for regioselectivity control 1,2-migratory insertion across unsymmetrical internal alkynes, as well direct products anti-insertion stereochemistry, have been devised. The alkenyl-to-aryl 1,4-metal migration upon metal recently exploited powerful cascade sequences leading complex polycyclic scaffolds, including development enantioselective processes. Elegant enantiospecific dynamic kinetic resolution methods developed accessing chiral allenes from propargylic alcohol derivatives. Mechanistic manifolds emerged based single-electron transfer (SET) that provided fresh impetus alkyne 1,2-difunctionalization complementary stereoselectivity processes relying 1,2-insertion R–M species. Herein, we discuss most recent advances transition-metal-catalyzed using reagents, categorized according type mechanistic outcome. Emphasis is placed aspects, synthetic utility, limitations, challenges future research.

Language: Английский

---

Iridium-Catalyzed Asymmetric Difunctionalization of C–C σ-Bonds Enabled by Ring-Strained Boronate Complexes

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(30), P. 16508 - 16516

Published: July 20, 2023

Enantioenriched organoboron intermediates are important building blocks in organic synthesis and drug discovery. Recently, transition metal-catalyzed enantioselective 1,2-metalate rearrangements of alkenylboronates have emerged as an attractive protocol to access these valuable reagents by installing two different carbon fragments across C═C π-bonds. Herein, we report the development iridium-catalyzed asymmetric allylation-induced rearrangement bicyclo[1.1.0]butyl (BCB) boronate complexes enabled strain release, which allows difunctionalization C-C σ-bonds, including dicarbonation carboboration. This provides a variety enantioenriched three-dimensional 1,1,3-trisubstituted cyclobutane products bearing boronic ester that can be readily derivatized. Notably, reaction gives trans diastereoisomers result from anti-addition σ-bond, is contrast syn-additions observed for reactions promoted PdII-aryl other electrophiles our previous works. The diastereoselectivity has been rationalized based on combination experimental data density functional theory calculations, suggest BCB highly nucleophilic react via early states with low activation barriers.

Language: Английский

---

Stereospecific 1,2‐Migrations of Boronate Complexes Induced by Electrophiles

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(39), P. 16859 - 16872

Published: June 27, 2020

The stereospecific 1,2-migration of boronate complexes is one the most representative reactions in boron chemistry. This process has been used extensively to develop powerful methods for asymmetric synthesis, with applications spanning from pharmaceuticals natural products. Typically, driven by displacement an α-leaving group, oxidation α-boryl radical, or electrophilic activation alkenyl complex. aim this article summarize recent advances rapidly expanding field electrophile-induced groups sp

Language: Английский

---

Difunctionalization of C–C σ-Bonds Enabled by the Reaction of Bicyclo[1.1.0]butyl Boronate Complexes with Electrophiles: Reaction Development, Scope, and Stereochemical Origins

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(39), P. 16766 - 16775

Published: Sept. 4, 2020

Difunctionalization reactions of C–C σ-bonds have the potential to streamline access molecules that would otherwise be difficult prepare. However, development such is challenging because are typically unreactive. Exploiting high ring-strain energy polycyclic carbocycles a common strategy weaken and facilitate reaction σ-bonds, but there limited examples highly strained being used in difunctionalization reactions. We demonstrate bicyclo[1.1.0]butyl boronate complexes (strain ca. 65 kcal/mol), which were prepared by reacting boronic esters with lithium, react electrophiles achieve diastereoselective central σ-bond unit. The shows broad substrate scope, range different successfully employed form diverse set 1,1,3-trisubstituted cyclobutanes (>50 examples) diastereoselectivity. diastereoselectivity observed has been rationalized based on combination experimental data DFT calculations, suggests separate concerted stepwise mechanisms operating, depending upon migrating substituent electrophile used.

Language: Английский

---

Asymmetric 1,4-functionalization of 1,3-enynes via dual photoredox and chromium catalysis

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: Aug. 26, 2022

Abstract The merger of photoredox and transition-metal catalysis has evolved as a robust platform in organic synthesis over the past decade. stereoselective 1,4-functionalization 1,3-enynes, prevalent synthon synthetic chemistry, could afford valuable chiral allene derivatives. However, tremendous efforts have been focused on ionic reaction pathway. radical-involved asymmetric 1,3-enynes remains prominent challenge. Herein, we describe three-component 1,4-dialkylation via dual chromium to provide allenols. This method features readily available starting materials, broad substrate scope, good functional group compatibility, high regioselectivity, simultaneous control axial central chiralities. Mechanistic studies suggest that this proceeds through redox-neutral

Language: Английский

---

Enantioselective Allylation of Alkenyl Boronates Promotes a 1,2-Metalate Rearrangement with 1,3-Diastereocontrol

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(13), P. 4921 - 4927

Published: March 23, 2021

Alkenyl boronates add to Ir(π-allyl) intermediates with high enantioselectivity. A 1,2-metalate shift forms a second C–C bond and sets 1,3-stereochemical relationship. The three-component coupling provides tertiary boronic esters that can undergo multiple additional functionalizations. An extension trisubstituted olefins three contiguous stereocenters.

Language: Английский

---

Catalytic Enantioconvergent Allenylation of Aldehydes with Propargyl Halides

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(10)

Published: Jan. 14, 2022

α-Allenol is a versatile synthon in organic synthesis. The catalytic asymmetric synthesis of α-allenols from readily available starting materials remains prominent challenge, especially when simultaneous control over axial and central chirality required. Herein, we describe the Cr-catalyzed enantioconvergent allenylation aldehydes with racemic propargyl halides to rapidly access wide range chiral adjacent chiralities. This method features excellent regio-, diastereo- enantioselectivity broad substrate scope, provides facile all four stereoisomers allied Mitsunobu reaction. Preliminary mechanistic studies support radical-based reaction pathways. synthetic utility demonstrated by application late-stage functionalization formal total (+)-varitriol.

Language: Английский

---