Enantio‐ and Diastereoselective Synthesis of Chiral Tetrasubstituted α‐Amino Allenoates Bearing a Vicinal All‐Carbon Quaternary Stereocenter with Dual‐Copper‐Catalysis

Angewandte Chemie, Год журнала: 2023, Номер 135(31)

Опубликована: Июнь 1, 2023

Abstract The skeletons of chiral tetrasubstituted allenes bearing a vicinal all‐carbon quaternary stereocenter are importance but still challenging to synthesize. Herein, we report enantio‐ and diastereoselective γ‐additions 1‐alkynyl ketimines with dual‐copper‐catalysis under mild conditions, affording α‐amino allenoates in high yields (up 99 % yield) excellent enantioselectivities ee ) diastereoselectivities >20 : 1 dr ). Importantly, the stereodivergent synthesis products was realized by asymmetric γ‐addition reaction Grignard reagent promoted epimerization. Moreover, dual‐copper‐catalyzed reactions were smoothly applied gram‐scale adopted introduce allenyl moieties into bioactive molecules. Mechanistic experiments density functional theory (DFT) calculations demonstrated that catalyzed double copper catalysts.

Язык: Английский

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Copper-Catalyzed Site-Selective C(sp²)–H Alkynylation of Allenes

ACS Catalysis, Год журнала: 2024, Номер 14(17), С. 13219 - 13226

Опубликована: Авг. 19, 2024

Conjugated allenynes serve as prominently featured structural units in various natural products. However, the absence of an efficient and adaptable synthesis has hindered their broader application synthetic endeavors biological investigations. In terms atom- step-economy, there is urgent need for strategy with a substrate scope compared to previous reports. Herein, we report copper-catalyzed allenic C(sp2)–H alkynylation array allenes exceptional site selectivity. While aliphatic C(sp3)–H bonds been extensively studied, radical-mediated regioselective allenyl via direct hydrogen atom transfer (HAT) from bond remains unresolved challenge chemistry. This difficulty arises inherent issues such addition radical intermediates or alkynes regioselectivity HAT process. Our protocol addresses these challenges demonstrates scope, tolerance toward functional groups, including active sp3 C–H benzyl groups ethers, results high diversity

Язык: Английский

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Distinctive Mechanistic Scenarios and Substituent Effects of Gold(I) versus Copper(I) Catalysis for Hydroacylation of Terminal Alkynes with Glyoxal Derivatives

The Journal of Organic Chemistry, Год журнала: 2022, Номер 87(17), С. 11681 - 11692

Опубликована: Авг. 19, 2022

Density functional theory (DFT) calculations have been conducted to study the mechanisms, substituent effects, and role of bases in Au- Cu-catalyzed hydroacylation terminal alkyne with glyoxal derivatives. The two reactions, despite being catalyzed by same group transition metals, follow distinctive reaction mechanisms. Through detailed DFT calculations, insights into mechanisms are obtained, effects understood.

Язык: Английский

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Dual Rh(II)/Pd(0) Relay Catalysis Involving Sigmatropic Rearrangement Using N-Sulfonyl Triazoles and 2-Hydroxymethylallyl Carbonates

Organic Letters, Год журнала: 2022, Номер 24(38), С. 6951 - 6956

Опубликована: Сен. 19, 2022

Dual Rh(II)/Pd(0) relay catalysis of N-sulfonyl triazoles and 2-hydroxymethylallyl carbonates has been developed, which affords pyrrolidines in moderate to good yields with high diastereoselectivities. The reaction proceeds via a mechanism involving O-H insertion onto the α-imino Rh(II)-carbene, [3,3]-sigmatropic rearrangement, dipole formation through Pd(0)-catalyzed decarboxylation, intramolecular N-allylation, leading multiple bonds one-pot operation.

Язык: Английский

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Functionalized Chromans from ortho-Quinone Methides and Arylallenes

The Journal of Organic Chemistry, Год журнала: 2022, Номер 87(23), С. 15863 - 15887

Опубликована: Ноя. 14, 2022

ortho-Quinone methides (o-QMs) underwent formal [4 + 2]-cycloaddition reactions with arylallenes regioselectively at the styrenyl olefin to furnish corresponding 3-methylene-2-arylchromans in moderate good yields (up 88%). When R ≠ H, also proceeded stereoselectivity 5:1) which was governed by nature of group. The could serve as common intermediates for further functionalization including epoxidation, oxidative cleavage/Baeyer–Villiger oxidation, Riley acid-catalyzed rearrangement, and Pd-catalyzed cross-coupling derivatives yields.

Язык: Английский

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Copper(I)‐Catalyzed Enantioselective Synthesis of Chiral Cyclohexenylallenes and Transfer of Axial to Center Chirality by Ytterbium (III) Catalyzed [4+2] Cycloaddition

Asian Journal of Organic Chemistry, Год журнала: 2024, Номер 13(5)

Опубликована: Март 21, 2024

Abstract Chiral cyclohexenylallenes are readily accessed from 1‐enynes, aldehydes and chiral secondary amines in good yields (up to 79 % yield) with excellent enantioselectivities 99 ee), through CuI catalyzed the formation of propargylamine intermediates. Subsequent Yb(OTf) 3 [4+2] cycloaddition reaction cyclohexylallenes dienophiles tetracyanoethylene diethyl acetylenedicarboxylate afforded corresponding bicyclic products 69–75 yield 84–90 ee.

Язык: Английский

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Use of 1-Chlorovinyl p-Tolyl Sulfoxides as Alkynylmagnesium Chloride Sources

Опубликована: Фев. 14, 2023

A method for generating alkynylmagnesium chlorides from 1-chlorovinyl p-tolyl sulfoxides and an isopropylmagnesium chloride-lithium chloride complex (turbo Grignard reagent) has been developed. The consists of a sulfoxide/magnesium exchange reaction turbo reagent, FritschButtenbergWiechell rearrangement the resulting magnesium alkylidene carbenoids, deprotonation terminal alkynes with reagent. are reacted variety electrophiles to generate internal alkynes.

Язык: Английский

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