Enantioselective functionalization at the C4 position of pyridinium salts through NHC catalysis DOI Creative Commons
Hangyeol Choi, Gangadhar Rao Mathi, Seonghyeok Hong

et al.

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

Published: April 1, 2022

Abstract A catalytic method for the enantioselective and C4-selective functionalization of pyridine derivatives is yet to be developed. Herein, we report an efficient asymmetric β-pyridylations enals that involve N-heterocyclic carbene (NHC) catalysis with excellent control over enantioselectivity pyridyl C4-selectivity. The key strategy precise stereocontrol involves enhancing interactions between chiral NHC-bound homoenolate pyridinium salt in presence hexafluorobenzene, which effectively differentiates two faces radical. Room temperature sufficient this transformation, reaction efficiency further accelerated by photo-mediation. This methodology exhibits broad functional group tolerance enables facile access a diverse range enantioenriched β-pyridyl carbonyl compounds under mild metal-free conditions.

Language: Английский

Radical NHC Catalysis DOI
Kun Liu, Max Schwenzer, Armido Studer

et al.

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(19), P. 11984 - 11999

Published: Sept. 19, 2022

Radical/radical cross-coupling reactions represent an efficient and straightforward approach for the construction of chemical bonds accordingly have drawn increasing attention over past decades. In order to achieve synthetically useful transformations, a persistent radical should be coupled with transient in accordance effect (PRE). However, known radicals outnumber by far types free radicals, which limits widespread application PRE, until today. Thus, development between has been focus, meanwhile transition-metal catalysis successfully implemented artificially prolong lifetimes, allowing their utilization formal radical/radical cross-couplings. Complementary research field recently uncovered that organocatalytically generated NHC-derived ketyl are type catalytically radicals. NHC-catalyzed transformations aldehydes carboxylic acid derivatives enabled disclosure ever-increasing number interesting reactions, different from traditional ionic processes, offering otherwise inaccessible activation modes. These discoveries opened door NHC organocatalysis manipulation reactions. Due its obvious potential synthetic organic chemistry, it is timely provide perspective on this emerging field.

Language: Английский

Citations

203
Benzylic C−H acylation by cooperative NHC and photoredox catalysis DOI Creative Commons
Qingyuan Meng, Lena Lezius, Armido Studer

et al.

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: April 6, 2021

Methods that enable site selective acylation of sp

Language: Английский

Citations

154
Direct α-Acylation of Alkenes via N-Heterocyclic Carbene, Sulfinate, and Photoredox Cooperative Triple Catalysis DOI
Kun Liu, Armido Studer

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(13), P. 4903 - 4909

Published: March 24, 2021

N-Heterocyclic carbene (NHC) catalysis has emerged as a versatile tool in modern synthetic chemistry. Further increasing the complexity, several processes have been introduced that proceed via dual catalysis, where NHC organocatalyst operates concert with second catalytic moiety, significantly enlarging reaction scope. In biological transformations, multiple is generally used to access complex natural products. Guided by strategy, triple studied recently, three different modes are merged single process. this Communication, direct α-C–H acylation of various alkenes aroyl fluorides using NHC, sulfinate, and photoredox cooperative reported. The method allows preparation α-substituted vinyl ketones moderate high yields excellent functional group tolerance. Mechanistic studies reveal these cascades through sequential radical addition/coupling/elimination contrast known operate two sets interwoven cycles, process, all cycles interwoven.

Language: Английский

Citations

151
Tale of the Breslow intermediate, a central player in N-heterocyclic carbene organocatalysis: then and now DOI Creative Commons
Monika Pareek, Yernaidu Reddi, Raghavan B. Sunoj

et al.

Chemical Science, Journal Year: 2021, Volume and Issue: 12(23), P. 7973 - 7992

Published: Jan. 1, 2021

Molecular insights on the formation, detection, and even isolation of Breslow intermediate, which is most important species in N-heterocyclic carbene (NHC) catalysis, as obtained from experimental computational studies, are presented.

Language: Английский

Citations

111
Recent advances in radical-mediated transformations of 1,3-dienes DOI

Peng‐Zi Wang,

Wen‐Jing Xiao, Jia‐Rong Chen

et al.

CHINESE JOURNAL OF CATALYSIS (CHINESE VERSION), Journal Year: 2022, Volume and Issue: 43(3), P. 548 - 557

Published: Feb. 2, 2022

Language: Английский

Citations

81
Radical transformations for allene synthesis DOI Creative Commons
Yajun Li, Hongli Bao

Chemical Science, Journal Year: 2022, Volume and Issue: 13(29), P. 8491 - 8506

Published: Jan. 1, 2022

Allenes are valuable organic molecules that feature unique physical and chemical properties. They not only often found in natural products, but also act as versatile building blocks for the access of complex molecular targets, such pharmaceuticals, functional materials. Therefore, many remarkable elegant methodologies have been established synthesis allenes. Recently, more methods radical allenes developed, clearly emphasizing associated great synthetic values. In this perspective, we will discuss recent important advances

Language: Английский

Citations

78
Synthesis of Cyclopropenols Enabled by Visible‐Light‐Induced Organocatalyzed [2+1] Cyclization DOI
Gang Zhou, Xiao Shen

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

Published: Jan. 7, 2022

Although the synthesis of common cyclopropenes has been well studied, access to cyclopropenols is rather limited. Herein, we report first α-trifluoromethylated via 2+1 cycloaddition reactions between alkynes and trifluoroacylsilanes, enabled by visible-light-induced organocatalysis. The novel ambiphilic donor-acceptor carbenes derived from trifluoroacetylsilanes reacted efficiently with both activated non-activated alkynes. reaction features simple operation, mild conditions, broad substrate scope good functional group tolerance. synthetic potential highlighted gram-scale cyclopropanols through combination cyclization high diastereoselective hydrogenation in one pot.

Language: Английский

Citations

74
NHC and visible light-mediated photoredox co-catalyzed 1,4-sulfonylacylation of 1,3-enynes for tetrasubstituted allenyl ketones DOI Creative Commons
Lihong V. Wang,

Ruiyang Ma,

Jiaqiong Sun

et al.

Chemical Science, Journal Year: 2022, Volume and Issue: 13(11), P. 3169 - 3175

Published: Jan. 1, 2022

The modulation of selectivity highly reactive carbon radical cross-coupling for the construction C-C bonds represents a challenging task in organic chemistry. N-Heterocyclic carbene (NHC) catalyzed transformations have opened new avenue acyl With this method, selective an with alkyl efficient was successfully realized. However, reaction radicals vinyl has been much less investigated. We herein describe NHC and visible light-mediated photoredox co-catalyzed 1,4-sulfonylacylation 1,3-enynes, providing structurally diversified valuable tetrasubstituted allenyl ketones. Mechanistic studies indicated that ketyl are formed from aroyl fluorides via oxidative quenching photocatalyst excited state, generated chemo-specific sulfonyl addition to finally, key provides

Language: Английский

Citations

73
First-Generation Organic Reaction Intermediates in Zeolite Chemistry and Catalysis DOI
Xuan Gong, Mustafa Çağlayan, Yiru Ye

et al.

Chemical Reviews, Journal Year: 2022, Volume and Issue: 122(18), P. 14275 - 14345

Published: Aug. 10, 2022

Zeolite chemistry and catalysis are expected to play a decisive role in the next decade(s) build more decentralized renewable feedstock-dependent sustainable society owing increased scrutiny over carbon emissions. Therefore, lack of fundamental mechanistic understanding these processes is critical "technical bottleneck" that must be eliminated maximize economic value minimize waste. We have identified, considering this objective, related first-generation reaction intermediates (i.e., carbocations, radicals, carbenes, ketenes, carbanions) zeolite highly underdeveloped or undervalued compared other streams (e.g., homogeneous catalysis). This limitation can often attributed technological restrictions detect such "short-lived reactive" at interface (gas-solid/solid-liquid); however, recent rise sophisticated spectroscopic/analytical techniques (including under situ/operando conditions) modern data analysis methods collectively compete unravel impact organic intermediates. comprehensive review summarizes state-of-the-art evaluates their existing challenges future prospects, contribute significantly "circular economy" initiatives.

Language: Английский

Citations

71
Radical Reactions with N-Heterocyclic Carbene (NHC)-Derived Acyl Azoliums for Access to Multifunctionalized Ketones DOI

Hui Cai,

Xiaoqun Yang,

Shi‐Chao Ren

et al.

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(11), P. 8270 - 8293

Published: May 13, 2024

As one of the most important key intermediates, NHC-bound acylazolium-based ionic transformations have been intensively explored in past two decades. With expeditious development NHC-catalyzed radical recent years, acylazolium chemistry has reached another level, with number relevant publications increasing significantly. However, a summary focused on acylations NHC-derived acyl azoliums classified according to mechanistic difference not reported. Such detailed classification and deep analysis provide opportunities for better understanding history trend this field. In review, reactions N-heterocyclic carbene (NHC)-derived are systematically introduced. The achievements challenges within area also summarized discussed at end.

Language: Английский

Citations

23