Catalytic, Enantioselective <i>Syn</i>-Oxyamination of Alkenes

Mumford, Emily M.; Hemric, Brett N.; Denmark, Scott E.

doi:10.1021/jacs.1c06750

Cited by 44 publications

(38 citation statements)

References 52 publications

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“…We subsequently explored the generality of our modular approach to N-heterocycles with sulfilimines derived from amines other than alkyl amines. Acyl-amine-derived sulfilimines ( 12 – 14 ) can also function as bifunctional reagents, which undergo cyclization with alkenes under the same reaction conditions to produce dihydrooxazoles ( 50 – 52 ) 53 , 54 . An intriguing reactivity was discovered when using sulfilimine 15 as substrate, providing tetrahydrobenzofuran 53 exclusively in 89% yield instead of an N-heterocycle.…”

Section: Resultsmentioning

confidence: 99%

Bifunctional sulfilimines enable synthesis of multiple N-heterocycles from alkenes

et al. 2022

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Intramolecular cyclization of nitrogen-containing molecules onto pendant alkenes is an efficient strategy for the construction of N-heterocycles, which are of paramount importance in, for example, pharmaceuticals and materials. Similar intermolecular cyclization reactions, however, are scarcer for nitrogen building blocks, including N-centred radicals, and divergent and modular versions are not established. Here we report the use of sulfilimines as bifunctional N-radical precursors for cyclization reactions with alkenes to produce N-unprotected heterocycles in a single step through photoredox catalysis. Structurally diverse sulfilimines can be synthesized in a single step, and subsequently engage with alkenes to afford synthetically valuable five-, six- and seven-membered heterocycles. The broad and diverse scope is achievable by a radical-polar crossover annulation enabled by the bifunctional character of the reagents, which distinguishes itself from all other N-centred-radical-based reactions. The modular synthesis of the sulfilimines allows for larger structural diversity of N-heterocycle products than is currently achievable with other single cyclization methods.

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Section: Resultsmentioning

confidence: 99%

Bifunctional sulfilimines enable synthesis of multiple N-heterocycles from alkenes

et al. 2022

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“…1 Thus, small molecule selenides have been widely used in organic synthesis. 2,3 In addition, due to the inherent characteristics of selenium atoms, selenium-containing polymers have unique properties, such as redox, 4,5 light, 6,7 radiation 8,9 and coordination 10,11 responsiveness, and have been widely used in different fields, including smart nanocarriers, 12,13 enzyme mimics, 14,15 shape memory materials, 7,16 and self-healing materials. [17][18][19] Due to the unique photo-reactivity and dynamic nature of the Se-Se bond, diselenide-containing polymers are being more extensively studied.…”

Section: Introductionmentioning

confidence: 99%

Diselenide–yne chemistry for selenium-containing linear polymer modification

et al. 2022

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“…To date, a wide variety of methods has been developed for the synthesis of 2-oxazolines, among which the electrophilic cyclization of alkenes and the use of stoichiometric reagents such as diethylaminosulfur trifluoride (DAST) or oxidants (e.g., iodine and NBS) are worth mentioning in particular . In general, 2-oxazolines are produced from aldehydes, olefins, carboxylic acids, esters, or nitriles . One recent example is a silver-promoted protocol for synthesizing 5-[(pentafluorosulfanyl)-methyl]-2-oxazolines, which leads to SF 5 -containing heterocycles .…”

Section: Introductionmentioning

confidence: 99%

Phosphorus-Based Organocatalysis for the Dehydrative Cyclization of N-(2-Hydroxyethyl)amides into 2-Oxazolines

et al. 2021

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A metal-free, biomimetic catalytic protocol for the cyclization of N-(2-hydroxyethyl)amides to the corresponding 2-oxazolines (4,5-dihydrooxazoles), promoted by the 1,3,5,2,4,6-triazatriphosphorine (TAP)-derived organocatalyst tris(o-phenylenedioxy)cyclotriphosphazene (TAP-1) has been developed. This approach requires less precatalyst compared to the reported relevant systems, with respect to the phosphorus atom (the maximum turnover number (TON) ∼ 30), and exhibits a broader substrate scope and higher functional-group tolerance, providing the functionalized 2-oxazolines with retention of the configuration at the C(4) stereogenic center of the 2-oxazolines. Widely accessible β-amino alcohols can be used in this approach, and the cyclization of N-(2-hydroxyethyl)amides provides the desired 2-oxazolines in up to 99% yield. The mechanism of the reaction was studied by monitoring the reaction using spectral and analytical methods, whereby an 18 O-labeling experiment furnished valuable insights. The initial step involves a stoichiometric reaction between the substrate and TAP-1, which leads to the in situ generation of the catalyst, a catechol cyclic phosphate, as well as to a pyrocatechol phosphate and two possible active intermediates. The dehydrative cyclization was also successfully conducted on the gram scale.

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Catalytic, Enantioselective Syn-Oxyamination of Alkenes

Cited by 44 publications

References 52 publications

Bifunctional sulfilimines enable synthesis of multiple N-heterocycles from alkenes

Bifunctional sulfilimines enable synthesis of multiple N-heterocycles from alkenes

Diselenide–yne chemistry for selenium-containing linear polymer modification

Phosphorus-Based Organocatalysis for the Dehydrative Cyclization of N-(2-Hydroxyethyl)amides into 2-Oxazolines

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