Oxidation Catalysis by an Aerobically Generated Dess–Martin Periodinane Analogue

Maity, Asim; Hyun, Sung-Min; Wortman, Alan; Powers, Dennis A.

doi:10.1002/anie.201804159

“…The Miyamoto-Uchiyama protocol requires a sterically hindered aldehyde and was applied to the glycol scission of 1,2-diols and the Hofmann rearrangement of primary amides with only 3 to 5 equivalents of isobutyraldehyde and 5 to 20 mol % of pentamethyliodobenzene. [23] Powers method, which was further refined for the formation of iodine(V) reagents, [28] uses 10 equivalents of acetaldehyde and 1 mol % of CoCl 2 as the initiator to promote the synthesis of (diacetoxy)iodoarenes from the corresponding aryl iodides in acetic acid. This system was named "oxidase catalysis" by the authors.…”

mentioning

confidence: 99%

Photoinduced Aerobic Iodoarene‐Catalyzed Spirocyclization of N‐Oxy‐amides to N‐Fused Spirolactams**

Habert

¹

,

Cariou

²

2020

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We report that the spirocyclization of N-oxy-amides to N-fused spirolactams can be achieved under photoinduced aerobic conditions, using a dual iodoarene/pyrylium catalytic system. 13 spirolactams were obtained in this manner and control experiments have shown that the reaction does not proceed if either one of the catalyst is omitted or in the absence of light and/or oxygen. INTRODUCTION: Hypervalent iodine(III) compounds have been known for 130 years, 1 yet interest in their reactivity was very modest until the eighties, before witnessing a dramatic surge in the 2000's. 2-4 They possess many advantages in terms of versatility, high selectivity and lack of toxicity; however, their use as a stoichiometric reagent remains a drawback. Indeed, the driving force behind their reactivity is the final release of one equivalent of iodoarene (Scheme 1a), such as iodobenzene. The liberation of a stoiC 50 and HFIP-derived D (Scheme 5b). For Kita's bis iodoarene catalyst, 38 the stabilization would come from the formation of µ-oxo species. CONCLUSION: Using the spiro-cyclization of amides as a model reaction, we have demonstrated that aerobic iodoarene catalysis can be enabled by relying on a pyrylium photocatalyst under blue light irradiation. This unprecedented dual organocatalytic system allows the use of low catalytic loading of both catalyst under very mild operating conditions. We are currently pursuing more thorough study of this dual catalyst system to gain a deeper understanding of the reaction parameters by experimental and theoretical methods. This will allow us to expand the range of transformations that can be accomplished using this strategy, including the development of asymmetric reactions. ASSOCIATED CONTENT Supporting Information includes, optimization studies and control experiments, detailed synthetic procedures, characterizations of the compounds and copies of the NMR spectra. This material is available free of charge via the Internet at http://pubs.acs.org.

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“…The Miyamoto‐Uchiyama protocol requires a sterically hindered aldehyde and was applied to the glycol scission of 1,2‐diols and the Hofmann rearrangement of primary amides with only 3 to 5 equivalents of iso ‐butyraldehyde and 5 to 20 mol % of pentamethyliodobenzene [23] . Powers’ method, which was further refined for the formation of iodine(V) reagents, [28] uses 10 equivalents of acetaldehyde and 1 mol % of CoCl 2 as the initiator to promote the synthesis of (diacetoxy)iodoarenes from the corresponding aryl iodides in acetic acid. This system was named “oxidase catalysis” by the authors [29] .…”

Section: Methodsmentioning

confidence: 99%

Photoinduced Aerobic Iodoarene‐Catalyzed Spirocyclization of N‐Oxy‐amides to N‐Fused Spirolactams**

Habert

¹

,

Cariou

²

2020

View full text Add to dashboard Cite

We report that the spirocyclization of N-oxy-amides to N-fused spirolactams can be achieved under photoinduced aerobic conditions, using a dual iodoarene/pyrylium catalytic system. 13 spirolactams were obtained in this manner and control experiments have shown that the reaction does not proceed if either one of the catalyst is omitted or in the absence of light and/or oxygen. INTRODUCTION: Hypervalent iodine(III) compounds have been known for 130 years, 1 yet interest in their reactivity was very modest until the eighties, before witnessing a dramatic surge in the 2000's. 2-4 They possess many advantages in terms of versatility, high selectivity and lack of toxicity; however, their use as a stoichiometric reagent remains a drawback. Indeed, the driving force behind their reactivity is the final release of one equivalent of iodoarene (Scheme 1a), such as iodobenzene. The liberation of a stoiC 50 and HFIP-derived D (Scheme 5b). For Kita's bis iodoarene catalyst, 38 the stabilization would come from the formation of µ-oxo species. CONCLUSION: Using the spiro-cyclization of amides as a model reaction, we have demonstrated that aerobic iodoarene catalysis can be enabled by relying on a pyrylium photocatalyst under blue light irradiation. This unprecedented dual organocatalytic system allows the use of low catalytic loading of both catalyst under very mild operating conditions. We are currently pursuing more thorough study of this dual catalyst system to gain a deeper understanding of the reaction parameters by experimental and theoretical methods. This will allow us to expand the range of transformations that can be accomplished using this strategy, including the development of asymmetric reactions. ASSOCIATED CONTENT Supporting Information includes, optimization studies and control experiments, detailed synthetic procedures, characterizations of the compounds and copies of the NMR spectra. This material is available free of charge via the Internet at http://pubs.acs.org.

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“…1,4-Diols such as 14 reacted with 3l to afford the corresponding lactones (Scheme 6, d), and amines were also oxidized to the corresponding imines 17a,b, oxime 17c and aromatic heterocycles 17d in good yields (Scheme 6, e). 84 With the reactivity profile of 3l established, we evaluated the potential to utilize aerobically generated 3l as an aerobic oxidation catalyst. Using 15 mol% of 3l, oxidation of cyclohexanol afforded cyclohexanone in 86% yield (optimized reaction conditions: nitromethane (CH 3 NO 2 ) as the solvent at 70 °C).…”

Section: Synpacts Syn Lettmentioning

confidence: 99%

“…Similar to stoichiometric chemistry, lactone 15 was obtained in 73% yield from the corresponding 1,4-diol 14. 84 Amine dehydrogenation could not be accomplished under aerobic oxidation catalysis, which may be due to undesired N-oxidation by reactive autoxidation intermediates. Together, these results constitute the first example of oxidation catalysis via aerobically generated I(V) intermediates.…”

Section: Synpacts Syn Lettmentioning

confidence: 99%

Hypervalent Iodine Chemistry as a Platform for Aerobic Oxidation Catalysis

Maity¹,

Powers

²

2018

Synlett

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Here, we highlight the recent development of aerobic oxidation catalysis via hypervalent I(III) and I(V) intermediates. The described chemistry intercepts reactive intermediates generated during aldehyde autoxidation to accomplish the oxidation of aryl iodides. The aerobically generated hypervalent iodine intermediates are utilized to couple an array of substrate functionalization chemistry to the reduction of O2.1 Introduction2 Chemistry of Aerobically Generated I(III) Intermediates3 Chemistry of Aerobically Generated I(V) Intermediates4 Conclusions

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Oxidation Catalysis by an Aerobically Generated Dess–Martin Periodinane Analogue

Cited by 32 publications

References 69 publications

Photoinduced Aerobic Iodoarene‐Catalyzed Spirocyclization of N‐Oxy‐amides to N‐Fused Spirolactams**

Photoinduced Aerobic Iodoarene‐Catalyzed Spirocyclization of N‐Oxy‐amides to N‐Fused Spirolactams**

Photoinduced Aerobic Iodoarene‐Catalyzed Spirocyclization of N‐Oxy‐amides to N‐Fused Spirolactams**

Hypervalent Iodine Chemistry as a Platform for Aerobic Oxidation Catalysis

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