Use of highly stereospecific 1,3-dipolar cycloadditions of cyclic nitrones with acetylenes in the preparation of novel heterocyclic ring systems

Bowman, W. Russell; Davies, Roy V.; Slawin, Alexandra M. Z.; Sohal, Gian S.; Titman, R. B.; Wilkins, D. J.

doi:10.1039/a602598f

Cited by 17 publications

(5 citation statements)

References 4 publications

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“…They have been used, for instance, as intermediates during the synthesis of glycosidase inhibitor analogues , and of functionalized pyrroles . Although a number of synthetic approaches to 1,2-oxazines are known, − the development of alternative strategies is of considerable interest. Oxazolo[3,4- b ]pyridazin-7-ones have been previously prepared on the basis of cyclization reactions of 3-aminooxazolidin-2-ones …”

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confidence: 99%

One-Pot Cyclizations of Dilithiated Oximes and Hydrazones with Epibromohydrin. Efficient Synthesis of 6-Hydroxymethyl-5,6-dihydro-4H-1,2-oxazines and Oxazolo[3,4-b]pyridazin-7-ones

et al. 2006

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The one-pot cyclization of dilithiated oximes with epibromohydrin provided a convenient and regioselective approach to 6-hydroxymethyl-5,6-dihydro-4H-1,2-oxazines. The reaction of the latter with phosphorus tribromide resulted in a Beckmann rearrangement and formation of 5-bromomethyl-2-iminotetrahydrofurans. The reaction of dilithiated hydrazones with epibromohydrin afforded oxazolo[3,4-b]pyridazin-7-ones, which were formed by a novel domino cyclization.

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confidence: 99%

One-Pot Cyclizations of Dilithiated Oximes and Hydrazones with Epibromohydrin. Efficient Synthesis of 6-Hydroxymethyl-5,6-dihydro-4H-1,2-oxazines and Oxazolo[3,4-b]pyridazin-7-ones

et al. 2006

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“…The hetero‐Diels–Alder reactions of nitroso compounds14 or the cycloaddition of nitrone15 are known as useful straightforward synthetic methods for 1,2‐oxazines. 1,2‐Oxazines are also available by the cyclization of alkenyl‐substituted oximes using NBS,16 diphenyl diselenide,17 acid,18 UV light,19 and iodine 20. Cyclization of γ‐sulfonyloximes,21 γ‐chlorooximes22 and γ,δ‐epoxyoxime23 by using base is also a method for the preparation of 1,2‐oxazines.…”

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confidence: 99%

Asymmetric Aldol Reaction of α‐Acetoxyimino Aldehydes and its Application in the Synthesis of Substituted 1,2‐Oxazine Derivatives

et al. 2014

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Abstract:We have developed an asymmetric crossaldol reaction of a-acetoxyimino aldehydes with aldehyde pro-nucleophiles, catalyzed by proline, to afford g-acetoxyimino-b-hydroxy aldehydes in good yield with excellent enantioselectivity. The obtained aldol products have been successfully converted to 1,2-oxazines with four contiguous chiral centers in excellent diastereoselectivity in one-pot via sequential reactions such as deacetylation, oxy-Michael reaction and reduction.

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“…Many examples of SCOE synthesis by the cyclization of γ,δ-unsaturated oxime derivatives 68 by selen electrophiles − or halogen − induction are known (Scheme ). Here, mixtures of dihydrooxazines 69 and cyclic nitrones 70 with the predominance of the latter, as a rule, are the products.…”

Section: Synthesis Of Six-membered Cyclic Oxime Ethers 1 Andmentioning

confidence: 99%

Chemistry of Six-Membered Cyclic Oxime Ethers. Application in the Synthesis of Bioactive Compounds

2011

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CONTENTS 1. Introduction 5004 2. Synthesis of Six-Membered Cyclic Oxime Ethers 1 and 2 5005 2.1. [4 þ 2]-Cycloaddition Reactions 5005 2.2. Intramolecular Cyclization of γ-Functionalized Oximes 5009 2.3. Intramolecular Cyclization of Functionalized O-Substituted Hydroxylamines 5012 2.4. Synthesis of SCOE from N-O-Containing Heterocyclic Derivatives 5012 2.4.1. Synthesis of SCOE from Other 1,2-Oxazines 5012 2.4.2. Synthesis of SCOE from Isoxazolines and Five-Membered Cyclic Nitronates 5014 2.5. Other Methods 5014 3. Chemical Properties of SCOE 5016 3.1. Reduction of SCOE 5016 3.1.1. Reduction of SCOE to Tetrahydro-2H-1,2oxazines 5018 3.1.2. Reduction of SCOE with 1,2-Oxazine Ring-Opening 5020 3.1.2.1. Reduction of SCOE to 1,4-Amino Alcohols. 5020 3.1.2.2. Reduction of SCOE to Carbonyl Compounds. 5021 3.1.2.3. Reduction of SCOE to γ-Hydroxyoximes. 5022 3.1.3. Reduction Reactions of SCOE with 1,2-Oxazine Ring Contraction 5022 3.1.3.1. Reduction of SCOE to Pyrrolidines. 5022 3.1.3.2. Reduction of SCOE to N-Hydroxypyrrolidines. 5023 3.1.3.3. Reduction of SCOE to Pyrroles. 5024 3.1.3.4. Reduction of SCOE to Aziridines. 5025 3.1.3.5. Reduction of SCOE to Furan Derivatives. 5025 3.2. Addition Reactions to the CdN Double Bond of SCOE 5026 3.3. 1,2-Oxazine Ring-Opening in SCOE 5027 3.4. Deoximation of SCOE 5028 3.5. 1,2-Oxazine Ring Rearrangements in SCOE 5028 3.6. 1,2-Oxazine Ring Fragmentation Reactions in SCOE 5030 4. SCOE in the Synthesis of Natural Products and Biologically Active Compounds 5031 4.1. Synthesis of Amino Acids 5032 4.2. Synthesis of Polyhydroxylated Pyrrolidines 5033 4.3. Synthesis of Pyrrolizidine and Indolizidine Alkaloids and Their Analogs 5033 4.4. Synthesis of Biologically Active 2-Aryl-Substituted Pyrrolidines and Amines 5035 4.5. Synthesis of Other Natural Compounds 5036 5. Conclusion 5037 Author Information 5037 Biographies 5038 Acknowledgment 5038 References 5038

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Use of highly stereospecific 1,3-dipolar cycloadditions of cyclic nitrones with acetylenes in the preparation of novel heterocyclic ring systems

Cited by 17 publications

References 4 publications

One-Pot Cyclizations of Dilithiated Oximes and Hydrazones with Epibromohydrin. Efficient Synthesis of 6-Hydroxymethyl-5,6-dihydro-4H-1,2-oxazines and Oxazolo[3,4-b]pyridazin-7-ones

One-Pot Cyclizations of Dilithiated Oximes and Hydrazones with Epibromohydrin. Efficient Synthesis of 6-Hydroxymethyl-5,6-dihydro-4H-1,2-oxazines and Oxazolo[3,4-b]pyridazin-7-ones

Asymmetric Aldol Reaction of α‐Acetoxyimino Aldehydes and its Application in the Synthesis of Substituted 1,2‐Oxazine Derivatives

Chemistry of Six-Membered Cyclic Oxime Ethers. Application in the Synthesis of Bioactive Compounds

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