A One-Pot Reaction of α-Imino Rhodium Carbenoids and Halohydrins: Access to 2,6-Substituted Dihydro-2<i>H</i>-1,4-oxazines

Jones, K.; Nutt, Michael J.; Comninos, Elena; Sobolev, Alexandre N.; Moggach, Stephen A.; Miura, Tomoya; Murakami, Masahiro; Stewart, Scott G.

doi:10.1021/acs.orglett.0c00947

Cited by 20 publications

(10 citation statements)

References 60 publications

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“…Stewart and co-workers demonstrated a facile method for the synthesis of 2,6-substituted dihydro-2 H -1,4-oxazines from α-imino rhodium carbenoids and halohydrins under basic conditions (Scheme ). The reaction proceeds through 1,3-insertion of the carbene into the O–H bond of the halohydrin and subsequent intramolecular nucleophilic displacement.…”

Section: Denitrogenative Transformations Of Triazolesmentioning

confidence: 99%

1,2,3-Triazole and Its Analogues: New Surrogates for Diazo Compounds

2022

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Readily accessible and shelf-stable 1,2,3-triazole and its analogues such as pyridotriazole, triazoloindole, benzotriazole, and thiadiazole exist in equilibrium with their ring-opened isomers, viz., diazo compounds. These ring-opened isomers could be trapped by various metal catalysts (e.g., Rh, Pd, Cu, Co, Ag, etc.) to generate the corresponding metal carbenoids with extrusion of nitrogen. As a consequence, these unique N-heterocycles facilitate access to a realm of N-containing complex structural motifs of biological importance through denitrogenative transformations such as transannulations, insertions, ylide formation, and rearrangements by trapping of the metal carbenoids with a diverse range of coupling partners (e.g., alkenes, alkynes, nitriles, carbo/heterocycles, X–H/C–X bonds, etc.). Hence, suitably substituted triazole derivatives have emerged as efficient surrogates of diazo compounds for the generation of reactive metal carbenoids during the past decades. In this comprehensive review, we aim to discuss in detail the remarkable advancement in their synthesis and synthetic applications.

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Section: Denitrogenative Transformations Of Triazolesmentioning

confidence: 99%

1,2,3-Triazole and Its Analogues: New Surrogates for Diazo Compounds

2022

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“…Last year, a Rh(II)-catalyzed strategy for the preparation of 2,6-disubstituted 3,4-dihydro-2H-1,4-oxazines 130 from Ntosyl-1,2,3-triazoles 9 and halohydrins 128 was reported by Stewart and co-workers (Scheme 29). [48] A variety of aryl and alkenyl C4-substituted triazoles and a number of halohydrins were utilized to demonstrate the substrate scope of this protocol. In addition, the reaction was successfully applied for the total synthesis of natural product (�)-chelonin C 132 in 51 % yield over three steps.…”

Section: Oà H Nà H Insertionmentioning

confidence: 99%

Catalytic Insertion Reactions of α‐Imino Carbenoids

Pal

Volla

2021

The Chemical Record

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Over the past decade, α-imino carbenoids generated via transition metal (such as rhodium, nickel, copper, palladium, silver) catalyzed denitrogenative ring-opening of N-sulfonyl-1,2,3-triazoles have found an extensive account of applications in synthetic organic chemistry. Particularly, they have been widely utilized as a donor/acceptor carbene complex in a range of transformations leading to diverse nitrogen containing compounds and heterocycles. Along the same direction, 3-diazoindolin-2-imines were successfully applied as an alternative source of αimino carbenoid precursors for the development of a number of methodologies to access diverse indole derivatives. This review summarizes the insertion reactions of α-imino metal carbenes derived from N-sulfonyl-1,2,3-triazoles and 3-diazoindolin-2-imines.

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“…Also, the synthesis of various six-membered heterocycles 38 and carbocycles 21 based on π-bond activation by organophotocatalysts has been reported. 10 Previous synthetic strategies for dihydro-1,4-oxazine derivatives were based on Ru 39 or Rh 40,41 metal carbene complexes. While photocatalytic [4 + 2] cycloaddition for the synthesis of 1,2-oxazines via the nitroso Diels−Alder reaction has been described, 42 the difficulty in accessing the optimal redox windows of the requisite reactants hampered the development of the corresponding reaction for the isomeric 1,4-oxazine synthesis.…”

Section: ■ Introductionmentioning

confidence: 99%

Synthesis of Bicyclic N-Heterocycles via Photoredox Cycloaddition of Imino-Alkynes and Imino-Alkenes

Ryou

Park

et al. 2021

ACS Catal.

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Cycloaddition reactions offer great advantages regarding atom and step economy for the construction of various carbocycles and heterocycles. While the recent development based on sensitized visible light photocatalysis allowed the synthesis of azetidines via imine-alkene [2 + 2] cycloaddition, imine-alkyne [2 + 2] cycloaddition under visible light photocatalysis has not been reported. In this regard, we report the synthesis of pyrrolizidinones based on intramolecular imine-alkyne [2 + 2] cycloaddition under visible light photocatalysis. This redox-neutral reaction involves formal imine-alkyne metathesis followed by redox-mediated annulation with concomitant rearrangement. In contrast, the use of imino-alkenes provides dihyro-1,4-oxazines via an alternative [4 + 2] cycloaddition pathway. The proposed reaction mechanisms were supported by control experiments and DFT calculations.

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A One-Pot Reaction of α-Imino Rhodium Carbenoids and Halohydrins: Access to 2,6-Substituted Dihydro-2H-1,4-oxazines

Cited by 20 publications

References 60 publications

1,2,3-Triazole and Its Analogues: New Surrogates for Diazo Compounds

1,2,3-Triazole and Its Analogues: New Surrogates for Diazo Compounds

Catalytic Insertion Reactions of α‐Imino Carbenoids

Synthesis of Bicyclic N-Heterocycles via Photoredox Cycloaddition of Imino-Alkynes and Imino-Alkenes

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