Visible-Light Photoredox-Catalyzed Synthesis of Nitrones: Unexpected Rate Acceleration by Water in the Synthesis of Isoxazolidines

Hou, Hong; Zhu, Shaoqun; Pan, Fangfang; Rueping, Magnus

doi:10.1021/ol500893g

Cited by 65 publications

(28 citation statements)

References 72 publications

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“…Using alkenes as the dipolarophiles, Rueping developed the first visible‐light‐mediated oxidative nitrone formation/[3 + 2] cycloaddition reaction for the synthesis of isoxazolidines 26 (Scheme ) . The aerobic oxidation of N ‐alkyl‐substituted hydroxylamines 24 to nitrones can be achieved through visible‐light photoredox catalysis under environmentally benign conditions, with low catalyst loading and no additional oxidant.…”

Section: The Synthesis Of N‐containing Heterocyclic Ringsmentioning

confidence: 99%

Synthesis ofN-Containing Heterocyclic Compounds Using Visible-light Photoredox Catalysis

Zhou

Hossain

Xiao

2016

The Chemical Record

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Nitrogen heterocycles represent a highly important class of compounds which are widely used in materials science, agrochemistry, and medicinal chemistry. Therefore, there is continuing interest in the development of convenient, efficient, and environmentally benign synthetic methods for the construction of nitrogen containing heterocycles. Due to its natural abundance, ease of use, and promising application in industry, the use of visible light as a driving force for chemical reactions has received considerable attention in the past few years. This account summarizes the synthesis of N-heterocycles using visible-light photoredox catalysis published in the last two years, according to the size and type of the formed N-heterocyclic rings. In the context of seminal works of others in this area, a concise summary of the contributions of the authors is also offered.

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Section: The Synthesis Of N‐containing Heterocyclic Ringsmentioning

confidence: 99%

Synthesis ofN-Containing Heterocyclic Compounds Using Visible-light Photoredox Catalysis

Zhou

Hossain

Xiao

2016

The Chemical Record

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“…Rueping continued to develop and broaden the field of photoredox-catalyzed [3+2] cycloadditions by developing a method for the synthesis of isoxazolidines from N-substituted hydroxylamines (Scheme 29). 24 Irradiation with an 11 W lamp in the presence of photoredox catalyst [Ir(ppy) 2 (bpy)]PF 6 provided the desired isoxazolidine. The reaction mechanism (Scheme 30) involved oxidation of the starting hydroxyamine to the corresponding aminium radical cation A.…”

Section: Scheme 28 Mechanism Of [3+2] Photocycloaddition Of Azomethinmentioning

confidence: 99%

Photochemical Synthesis of Azaheterocycles

Tanoury

2016

Synthesis

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Synthetic organic photochemistry is a field that continues to offer unique routes to organic structures not typically accessed from thermal reactions. In this review, the photochemical synthesis of five-, six-, seven-, and eight-membered-ring azaheterocycles, as well as some aza-macrocycles, is discussed. The discussion will focus on methods where heterocycle formation occurs during or as a result of a photochemical event. Reaction mechanisms will be discussed also, as these provide a rationale for understanding the synthetic results. 1 Introduction 2 Five-Membered Rings 2.1 Cyclization Reactions 2.2 Cycloadditions 2.3 From Aromatic and Vinyl Azides 2.4 earrangements 2.5 Other Individual Methods 3 Six-Membered Rings 3.1 Cyclization Reactions 3.2 Isocyanide Insertions 3.3 Cycloadditions 4 Seven-Membered Rings and Larger 5 Conclusion Key words azaheterocycles, photocycloaddition, photocyclization, photorearrangement, photocatalyst Dr. Tanoury began his career in the pharmaceutical industry in 1992 as a Medicinal Chemist at the Burroughs-Wellcome Company in North Carolina. In 1996, he moved to Sepracor, Inc. in Massachusetts to start a career as a process development chemist. He moved to Vertex Pharmaceuticals in 2001 where he is currently a Senior Scientific Fellow in the Process Chemistry Department. Prior to starting his industrial career, Dr. Tanoury was a graduate student under the direction of Professor Barry M. Trost, earning his Ph.D. from Stanford University in 1989. This was followed by a National Institutes of Health postdoctoral fellowship at Harvard University from 1989-1992 in the labs of Professor E. J. Corey. In addition to synthetic organic chemistry and developing chemical processes for the manufacture of API, Dr. Tanoury's interests include understanding and probing chemical reactions using state-ofthe-art technology, and studying reaction mechanisms and chemical properties (ground and excited state) using theoretical/computational methods.

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“…6,7 Since the strategies based on the oxidative formation of nitrones use metal-catalytic systems, harsh conditions and excess amounts of oxidants, 8 a common and mild method for synthesis of nitrones is based on the C=N bond formation by condensation. 9 However, this method also has limitation such as forming water during condensation which has decreased the yield of synthesized nitrones. 10,11 Furthermore, due to the use of hydroxylamines as hydrochloride salts, basemediated liberation of hydrochloride is commonly required.…”

Section: Introductionmentioning

confidence: 99%

A green synthesis of nitrones in glycerol

2019

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Visible-Light Photoredox-Catalyzed Synthesis of Nitrones: Unexpected Rate Acceleration by Water in the Synthesis of Isoxazolidines

Abstract: A new oxidative [3 + 2] cycloaddition of N-substituted hydroxylamines with alkenes was established under visible light photoredox catalysis. This novel protocol provides a rapid, mild, and efficient access to valuable five-membered ring isoxazolidine heterocycles in a concise fashion.

Cited by 65 publications

References 72 publications

Synthesis ofN-Containing Heterocyclic Compounds Using Visible-light Photoredox Catalysis

Synthesis ofN-Containing Heterocyclic Compounds Using Visible-light Photoredox Catalysis

Photochemical Synthesis of Azaheterocycles

A green synthesis of nitrones in glycerol

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