A Facile One-Pot Synthesis of 3,5-Disubstituted Isoxazole Derivatives Using Hydroxy (Tosyloxy) Iodobenzene

Various diethyl 3‐arylisoxazole‐4,5‐dicarboxylates were efficiently prepared in good to moderate yields by the successive treatment of benzylic chlorides and alkyl p‐tosylates with N‐methylmorpholine N‐oxide (NMO) and then hydroxylamine hydrochloride and potassium carbonate followed by Oxone® and diethyl acetylenedicarboxylates. This one‐pot proccess was carried out under mild, transition‐metal‐free conditions.

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“…Ethyl 3‐(4′‐Chlorophenyl)isoxazole‐5‐carboxylate (2a‐III): Colorless solid (186.5 mg, 60 % yield); m.p. 129–130 °C.…”

Section: Methodsmentioning

confidence: 99%

One‐Pot Preparation of 3‐Arylisoxazole‐4,5‐dicarboxylates from Benzylic Chlorides and Acetylenedicarboxylates

Imai

Togo

2018

Eur J Org Chem

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“…[17][18][19] In particular, the reaction of various aldoximes with alkynes in the presence of organohypervalent iodine(III) reagents such as DIB, 48,51,[54][55][56][57] BTI, 46,58,59 Koser's reagent, 49,60 or PhIO, 27,61 leads to oxidative heterocyclization yielding the corresponding isoxazoles. This procedure is applicable to various internal or terminal alkynes under mild condition.…”

Section: Cycloaddition Of Aldoximes Leading To Isoxazolesmentioning

confidence: 99%

“…© ARKAT USA, Inc Several oxidative cycloaddition reactions of internal alkynes with aldoximes using iodine(III) reagents have been reported. 46,54,60 The reactions of strained cyclic alkynes such as cyclooctyne derivatives with nitrile oxides generated from aldoximes and iodine(III) reagents are especially important in bioorthogonal chemistry. [55][56][57][58] For example, the reaction of lactose oxime with dibenzocyclooctyne derivatives using DIB gives the corresponding isoxazoles in good yields.…”

Section: Cycloaddition Of Aldoximes Leading To Isoxazolesmentioning

confidence: 99%

Oxidative cyclizations of oximes using hypervalent iodine reagents

Yoshimura

Zhdankin²

2017

Arkivoc

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This account overviews oxidative cyclization reactions of aldoximes or ketoximes promoted by hypervalent iodine reagents. The oxidation of aldoximes by iodine(III) compounds generates nitrile oxides which can further react with appropriate substrates via intermolecular or intramolecular 1,3-dipolar cycloaddition reactions leading to a variety of nitrogen and oxygen heterocycles. Hypervalent iodine reagents can also react with ketoximes producing the corresponding heterocyclic products via intramolecular cyclization reactions. Recently, the oxidative cyclization reactions of aldoximes have been realized under catalytic conditions mediated by hypervalent iodine active species.

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“…Subsequently, the reactive 1,3-dipolar nitrile oxide 67 was treated with various alkynes 68 to afford trisubstituted isoxazoles 69 in good yields (Scheme 12) [28]. Subsequently, the reactive 1,3-dipolar nitrile oxide 67 was treated with various alkynes 68 to afford trisubstituted isoxazoles 69 in good yields (Scheme 12) [28].…”

Section: Disubstituted Isoxazolesmentioning

confidence: 99%