Oxazine ring construction: methods and applications to natural product synthesis

Wan, Xiaobo; Joullié, Madeleine M.

doi:10.1007/s11458-009-0037-4

Cited by 8 publications

(5 citation statements)

References 39 publications

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“…In fact, the weakness of the N−O bond makes the 1,2‐oxazine scaffold useful for further functionalization, allowing to obtain numerous other structures. The synthesis and reactivity of 1,2‐oxazines have been reviewed many times,,, so that a complete list of the investigated reactions is not possible here. We just mention that the selective transformation of 1,2‐oxazines to cyclic or acyclic amino alcohols or amino sugars, oxazepinones, and pyrroles, are significant examples of how these heterocycles play a pivotal role in synthetic chemistry.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of 3,6‐Dihydro‐2H‐[1, 2]‐Oxazines from Nitroarenes and Conjugated Dienes, Catalyzed by Palladium/Phenanthroline Complexes and Employing Phenyl Formate as a CO Surrogate

et al. 2018

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Palladium/phenanthroline catalyzed reduction of nitroarenes by in situ‐generated carbon monoxide, from the decomposition of phenyl formate, affords the corresponding nitrosoarenes. The latter are trapped by conjugated dienes to give the corresponding 3,6‐dihydro‐2H‐[1, 2]‐oxazines (hetero Diels‐Alder adducts). Many functional groups are well tolerated. Yields are higher than those obtainable by any previously reported method, including the direct reaction of the diene with the pure nitrosoarene. The reaction can be performed in a single standard glass pressure tube, without the need for autoclaves or high‐pressure CO lines.

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Section: Introductionmentioning

confidence: 99%

Synthesis of 3,6‐Dihydro‐2H‐[1, 2]‐Oxazines from Nitroarenes and Conjugated Dienes, Catalyzed by Palladium/Phenanthroline Complexes and Employing Phenyl Formate as a CO Surrogate

et al. 2018

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“…Natural products, trichodermamide AÀ C, petrichodermamide A, aspergillazine A, and gliovirin, consist 1,2-oxazine skeleton, and these natural products possess exciting biological activities. [11] The synthetic methodology discussed in this study might have a good value for the synthesis of natural products or famous rings. [12] A method known in the literature was used for the synthesis of ynone-oxime derivatives (Scheme S1-S2 in supporting information).…”

mentioning

confidence: 99%

Gold‐catalyzed Cyclization of Non‐conjugated Ynone‐oxime Derivatives: Incorporation of Solvent Molecule

Taşdemir

Mengeş

2020

Asian J Org Chem

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Au ııı-promoted cyclization reaction of ynoneoxime derivatives furnished 4H-1,2-oxazine ring under mild reaction conditions. When an alcohol is present in the reaction media, it was attached to the oxazine ring by the second activation of cyclic intermediate with a gold catalyst. Cholesterol, propargyl alcohol, phenol, and some of the different alcohol derivatives with alkyl chain were bonded to the oxazine ring in good yields. While amine derivatives did not attach to the ring under optimized reaction conditions, the molecule with the thiol group deactivated the gold catalyst under the same reaction conditions and did not give any cyclic products. With the obtained cyclization protocol, 11 unknown oxazine derivatives were synthesized and characterized. The proposed cyclization mechanism was drawn according to the two independent control experiments, DFT optimization, and NBO charges.

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“…Such complex bioactive compounds have drawn much attention from synthetic chemists [9] . However, only two desulfurized products, 3 and trichodermamide B, have been acquired through racemic or enantioselective total synthetic strategies and required laborious reaction steps for construction of the 1,2‐oxazine ring (Figure S2) [10] .…”

Section: Introductionmentioning

confidence: 99%

Pretrichodermamide A Biosynthesis Reveals the Hidden Diversity of Epidithiodiketopiperazines

et al. 2023

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Fungal epidithiodiketopiperazines (ETPs) possess large structural diversity and complexity due to modifications of the cyclodipeptide skeleton. Elucidation of the biosynthetic pathway of pretrichodermamide A (1) in Trichoderma hypoxylon revealed a flexible catalytic machinery of multiple enzymes for generating ETP diversity. Seven tailoring enzymes encoded by the tda cluster are involved in 1 biosynthesis, that is, four P450s TdaB and TdaQ for 1,2‐oxazine formation, TdaI for C7′‐hydroxylation, and TdaG for C4, C5‐epoxidation, two methyltransferases TdaH for C6′‐ and TdaO for C7′‐O‐methylation, and a reductase TdaD for furan opening. Gene deletions led to the identification of 25 novel ETPs, including 20 shunt products, indicating the catalytic promiscuity of Tda enzymes. Particularly, TdaG and TdaD accept various substrates and catalyze regiospecific reactions at different stages of 1 biosynthesis. Our study not only uncovers a hidden library of ETP alkaloids, but also helps to understand the hidden chemical diversity of natural products by pathway manipulation.

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Oxazine ring construction: methods and applications to natural product synthesis

Cited by 8 publications

References 39 publications

Synthesis of 3,6‐Dihydro‐2H‐[1, 2]‐Oxazines from Nitroarenes and Conjugated Dienes, Catalyzed by Palladium/Phenanthroline Complexes and Employing Phenyl Formate as a CO Surrogate

Synthesis of 3,6‐Dihydro‐2H‐[1, 2]‐Oxazines from Nitroarenes and Conjugated Dienes, Catalyzed by Palladium/Phenanthroline Complexes and Employing Phenyl Formate as a CO Surrogate

Gold‐catalyzed Cyclization of Non‐conjugated Ynone‐oxime Derivatives: Incorporation of Solvent Molecule

Pretrichodermamide A Biosynthesis Reveals the Hidden Diversity of Epidithiodiketopiperazines

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