Catalytic Asymmetric Synthesis of Stable Oxetenes via Lewis Acid-Promoted [2 + 2] Cycloaddition

Aikawa, Kohsuke; Hioki, Yūta; Shimizu, Nobujiro; Mikami, Kōichi

doi:10.1021/ja2085299

Cited by 89 publications

(41 citation statements)

References 53 publications

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“…[22] In this case, the benzene-fused oxetene ring is unstable, and its fragmentation leads to the formation of αamino-α-unsaturated ketone C. [9,23] Through effective push-pull of the lone pair of electrons of the dimethylamino group in intermediate C, benzoyl cyanide is incorporated into the product through reasonable intermediate D. First, benzyne intermediate A is in situ generated by treatment of benzyne surrogate 1a with the fluoride anion.…”

Section: Resultsmentioning

confidence: 99%

Three‐Component Synthesis of α‐Amino‐α‐aryl Carbonitriles from Arynes, Aroyl Cyanides, and N,N‐Dimethylformamide

et al. 2014

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A general and efficient synthesis of α‐amino‐α‐aryl carbonitriles through the three‐component reaction of arynes, aroyl cyanides, and DMF in a single step is described. DMF was not only used as the solvent, but it also participated in the reaction as a component. Used as the cyanide sources, the aroyl cyanides solved the toxicity and solubility problems associated with the use of HCN or metal cyanides in the Strecker synthesis. This procedure furnished α‐amino‐α‐aryl carbonitriles in moderate to good yields with broad substrate scope. Moreover, this reaction could be performed under mild conditions with high atom economy.

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Section: Resultsmentioning

confidence: 99%

Three‐Component Synthesis of α‐Amino‐α‐aryl Carbonitriles from Arynes, Aroyl Cyanides, and N,N‐Dimethylformamide

et al. 2014

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“…[37] 2. gem-dimethyl group resultsi ni mproved VDR affinity. [37] 2. gem-dimethyl group resultsi ni mproved VDR affinity.…”

Section: Synthetic Routes To Oxetane Derivativesmentioning

confidence: 99%

The Current Status of O‐Heterocycles: A Synthetic and Medicinal Overview

Singh

Silakari

2018

ChemMedChem

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O-Heterocycles have been explored in the field of medicinal chemistry for a long time, but their significance has not been duly recognised and they are often shunned in favour of N-heterocycles. The design of bioactive molecules for nearly every pathophysiological condition is primarily focused on novel N-heterocycles. The main reasons for such bias include the ease of synthesis and possible mimicking of physiological molecules by N-heterocycles. But considering only this criterion rarely provides breakthrough molecules for a given disease condition, and instead the risks of toxicity or side effects are increased with such molecules. On the other hand, owing to improved synthetic feasibility, O-heterocycles have established themselves as equally potent lead molecules for a wide range of pathophysiological conditions. In the last decade there have been hundreds of reports validating the fact that equally potent molecules can be designed and developed by using O-heterocycles, and these are also expected to have comparably low toxicity. Even so, researchers tend to remain biased toward the use of N-heterocycles over O-heterocycles. Thus, this review provides a critical analysis of the synthesis and medicinal attributes of O-heterocycles, such as pyrones, oxazolones, furanones, oxetanes, oxazolidinones, and dioxolonones, and others, reported in the last five years, underlining the need for and the advantages guiding researchers toward them.

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“…With the tetrahydrofuran compound 8 the product was the known alkyne 26 (56%) (Scheme 6), which showed good agreement with literature spectroscopic data, 27,28 while for the tetrahydropyran compound 14, the expected alkyne product 27 (46%) was accompanied by the isomeric allene 28 (20% Simple oxetes such as this are almost unknown but there has been recent interest in more highly substituted examples such as the 4-methylene compounds 35 obtained by gold-catalysed cyclisation of α-hydroxybenzylallenes, 31 and stable fully substituted compounds 36 prepared in high enantiomeric purity from ethyl trifluoropyruvate and alkynes. 32 The parent compound has also been generated 33 We rationalise the formation of 30, as shown in Scheme 7, by initial loss of Ph 3 P from ylide 16 to give the carbene 31 which undergoes intramolecular oxonium ylide formation to form 32. This can then rearrange as shown to give 33, which loses CO and acetone to afford the oxete.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, structure and pyrolysis of stabilised phosphonium ylides containing saturated oxygen heterocycles

et al. 2016

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A range of twelve stabilised phosphonium ylides containing tetrahydrofuran, tetrahydropyran or 2,2-dimethyl-1,3-dioxolane rings have been prepared and fully characterised, including one X-ray structure determination of each type. The X-ray structures confirm the PvC and CvO functions to be syn and all the compounds undergo thermal extrusion of Ph 3 PO to give the corresponding alkynes. In some cases there is also competing loss of Ph 3 P to give different carbene-derived products and evidence has been obtained for the generation of 2-phenyloxete in this way. Raising the pyrolysis temperature leads in several cases to new secondary reactions of the alkyne products involving a sequence of alkyne to vinylidene isomerisation, intramolecular CH insertion, and retro Diels Alder reaction.

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Catalytic Asymmetric Synthesis of Stable Oxetenes via Lewis Acid-Promoted [2 + 2] Cycloaddition

Cited by 89 publications

References 53 publications

Three‐Component Synthesis of α‐Amino‐α‐aryl Carbonitriles from Arynes, Aroyl Cyanides, and N,N‐Dimethylformamide

Three‐Component Synthesis of α‐Amino‐α‐aryl Carbonitriles from Arynes, Aroyl Cyanides, and N,N‐Dimethylformamide

The Current Status of O‐Heterocycles: A Synthetic and Medicinal Overview

Synthesis, structure and pyrolysis of stabilised phosphonium ylides containing saturated oxygen heterocycles

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