P-Stereogenic Phosphorus Ligands in Asymmetric Catalysis

Chemical Reviews, Год журнала: 2024, Номер 124(14), С. 8657 - 8739

Опубликована: Июль 2, 2024

Chiral phosphorus ligands play a crucial role in asymmetric catalysis for the efficient synthesis of useful optically active compounds. They are largely categorized into two classes: backbone chirality and P-stereogenic ligands. Most reported belong to former class. Privileged ones such as BINAP DuPhos frequently employed wide range catalytic transformations. In contrast, latter class has remained small family many years mainly because their synthetic difficulty. The late 1990s saw emergence novel with superior enantioinduction ability Rh-catalyzed hydrogenation reactions. Since then, numerous have been synthesized used This Review summarizes thus far, including stereochemical electronic properties that afford high excellent enantioselectivities. Examples reactions use this described together applications construction key intermediates natural products therapeutic agents. literature covered dates back 1968 up until December 2023, centering on studies published later years.

Язык: Английский

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Enantio‐ and Regioselective Cascade Hydroboration of Methylenecyclopropanes for Facile Access to Chiral 1,3‐ and 1,4‐Bis(boronates)

Advanced Science, Год журнала: 2024, Номер 11(21)

Опубликована: Март 13, 2024

Abstract Chiral 1, n‐bis(boronate) plays a crucial role in organic synthesis and medicinal chemistry. However, their catalytic asymmetric has long posed challenge terms of operability accessibility from readily available substrates. The recent discovery the C═C bond formation through β‐C elimination methylenecyclopropanes (MCP) provided an exciting opportunity to enhance molecular complexity. In this study, catalyzed cascade hydroboration MCP is developed. By employing different ligands, various homoallylic boronate intermediate are obtained ring opening process. Subsequently, with HBpin or B 2 pin resulted enantioenriched chiral 1,3‐ 1,4‐bis(boronates) high yields, accompanied by excellent chemo‐ enantioselectivities. selective transformation these two distinct C─B bonds also demonstrated application potential synthesis.

Язык: Английский

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Cobalt-Catalyzed Enantioselective Hydroboration of α-Substituted Acrylates

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(10), С. 6604 - 6617

Опубликована: Март 3, 2024

Even though metal-catalyzed enantioselective hydroborations of alkenes have attracted enormous attention, few preparatively useful reactions α-alkyl acrylic acid derivatives are known, and most use rhodium catalysts. No examples asymmetric hydroboration the corresponding α-arylacrylic esters known. In our continuing efforts to search for new applications earth-abundant cobalt catalysts broadly applicable organic transformations, we identified 2-(2-diarylphosphinophenyl)oxazoline ligands mild reaction conditions efficient highly regio- α-alkyl- α-aryl- acrylates, giving β-borylated propionates. Since C-B bonds in these compounds can be readily replaced by C-O, C-N, C-C bonds, intermediates could serve as valuable chiral synthons, some from feedstock carbon sources, synthesis propionate-bearing motifs including polyketides related molecules. Two-step syntheses "Roche" ester methyl methacrylate (79%; er 99:1), arguably widely used fragment polyketide synthesis, tropic (∼80% yield; ∼93:7), which potential several medicinally important classes compounds, illustrate power methods. Mechanistic studies confirm requirement a cationic Co(I) species [(

Язык: Английский

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Chemodivergent, Regio‐ and Enantioselective Cycloaddition Reactions between 1,3‐Dienes and Alkynes

Angewandte Chemie International Edition, Год журнала: 2022, Номер 62(8)

Опубликована: Дек. 15, 2022

Alkynes and 1,3-dienes are among the most readily available precursors for organic synthesis. We report two distinctly different, catalyst-dependent, modes of regio- enantioselective cycloaddition reactions between these classes compounds providing rapid access to highly functionalized 1,4-cyclohexadienes or cyclobutenes from same precursors. Complexes an earth abundant metal, cobalt, with several commercially chiral bisphosphine ligands narrow bite angles catalyze [4+2]-cycloadditions a 1,3-diene alkyne giving cyclohexa-1,4-diene in excellent chemo-, enantioselectivities. In sharp contrast, complex finely tuned phosphino-oxazoline ligand promotes unique [2+2]-cycloaddition terminal double bond diene cyclobutene

Язык: Английский

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Borylation of Stable C(sp³)–O Bonds of Alkyl Esters over Supported Au Catalysts

Organic Letters, Год журнала: 2024, Номер 26(15), С. 2902 - 2907

Опубликована: Апрель 4, 2024

We report herein that supported gold catalysts efficiently promote the borylation of stable C(sp3)–O bonds alkyl esters. The use a disilane as an electron source and nanoparticles single-electron transfer catalyst is key to generating radicals via homolysis bonds, thereby enabling cross-coupling between bis(pinacolato)diboron linear cyclic esters afford diverse boronates.

Язык: Английский

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Catalysis and Synthesis Enabled by P-Chiral Dihydrobenzooxaphosphole Ligands

Organic Process Research & Development, Год журнала: 2024, Номер 28(4), С. 949 - 977

Опубликована: Апрель 8, 2024

P-Chiral phosphorus ligands received little attention in organic chemistry until Knowles made his landmark contribution asymmetric hydrogenation by developing the P-chiral CAMP and DIPAMP. The development of accelerated end last century with advent some highly efficient renowned for hydrogenation, including BisP*, TangPhos, QuinoxP*, DuanPhos, et al. However, most reported were air-sensitive, difficult to make, or lacked structural modularity, hampering their availability applicability. sterically electronically tunable is particularly desirable. Over past decade, a family hindered, electron-rich, structurally tunable, air-stable dihydrobenzooxaphosphole emerged that proved be versatile various transformations. 5 years witnessed an increasing number studies related these discovery unprecedented catalytic properties This review highlights unique catalysis applications synthesis natural products therapeutic agents.

Язык: Английский

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Enantioselective Synthesis of Secondary Homoallyl Borons by Copper-Catalyzed 1,1-Borylallylation of Terminal Alkynes

ACS Catalysis, Год журнала: 2024, Номер 14(16), С. 12102 - 12109

Опубликована: Июль 30, 2024

The development of a single catalyst system that enables cascade reaction processes involving multiple components to occur in highly chemo-, regio-, and enantioselective manner presents significant challenge catalysis. Here, we introduce direct catalytic asymmetric synthesis enantioenriched secondary homoallyl borons by assembling four readily available components─terminal alkynes, boron reagents (HBdan), silyl hydrides (PMHS), allyl electrophiles─in hydroboration hydroallylation sequence. This complex assembly line is delicately controlled copper catalyst, effectively overcoming side reactions. features simple starting materials, mild conditions, structurally diverse products, high regio- enantioselectivities (up >20:1 r.r. 94% ee). utility the resulting products showcased through their versatile transformations further demonstrated formal total syntheses natural such as (−)-bruguierol A, (−)-enterolactone, (−)-antofine. Mechanistic studies were conducted illuminate operative pathway, key intermediates, crucial roles hydride source PMHS.

Язык: Английский

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Asymmetric dihydroboration of allenes enabled by ligand relay catalysis

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Сен. 18, 2024

Язык: Английский

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Ligand Effects in Carboxylic Ester- and Aldehyde-Assisted β-C–H Activation in Regiodivergent and Enantioselective Cycloisomerization–Hydroalkenylation and Cycloisomerization–Hydroarylation, and [2 + 2 + 2]-Cycloadditions of 1,6-Enynes

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(27), С. 18753 - 18770

Опубликована: Июнь 27, 2024

Herein, we report room temperature, atom-economic protocols for high regio- and enantioselective tandem cycloisomerization–hydroarylation cycloisomerization–hydroalkenylation of 1,6-enynes leading to vicinal carba-functionalized pyrrolidines, tetrahydrofurans, cyclopentanes. The latter steps in these processes involve carbonyl-coordination-assisted ortho-C–H activation aromatic aldehydes esters, and, a similar, yet rarely seen, β-C–H the case acrylates. Synthetically useful versions such reactions are rare limited C2–H indoles pyrroles. A similar reaction is also observed with N-vinylphthalimide, which has carbonyl group suitable C–H activation. dibenzooxaphosphole ligand, (2S,2S′,3S,3S′)-MeO-BIBOP was uniquely identified as crucial achieving challenging enantioselectivity. This methodology gives access substituted five-membered carbo- heterocyclic compounds good yields excellent enantioselectivities under low catalyst loading. primary KIE 3.5 an intermolecular competition experiment methyl benzoate d5-methyl benzoate, indicates that cleavage turnover-limiting step this process. Unlike acrylates, undergoes exclusive hydroalkenylation, β, γ-unsaturated ester, but-3-enoate, highly cycloisomerization-coupling sequence 1,6-enyne giving either [2 + 2 2]-cycloaddition (S, S)-BDPP or hydroalkenylation (2S,2′S,3S,3′S)-MeO-BIBOP depending on ligand employed. (E)-configuration newly formed double bond at terminal alkynyl carbon (of starting enyne) product β,γ-unsaturated ester suggests more classical migratory insertion-β-hydride elimination route formation product.

Язык: Английский

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Rhodium-Catalyzed Highly Enantioselective Hydroboration of Acyclic Tetrasubstituted Alkenes Directed by an Amide

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(23), С. 16194 - 16202

Опубликована: Июнь 4, 2024

Although progress has been made in enantioselective hydroboration of di- and trisubstituted alkenes over the past decades, tetrasubstituted with high diastereo- enantioselectivities continues as an unmet challenge since 1950s due to its extremely low reactivity difficulties simultaneously control regio- stereoselectivity a alkene. Here, we report highly regio-, diastereo-, catalytic diverse acyclic alkenes. The delicate interplay electron-rich rhodium complex coordination-assistance forms adaptive catalyst that effectively overcomes controls stereoselectivity. generality system is exemplified by efficacy across various steric electronic properties.

Язык: Английский

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