Further Improvements of the Synthesis of Alkynes from Aldehydes.

Roth, Gerald J.; Liepold, Bernd; Mueller, S.; Bestmann, H. J.

doi:10.1002/chin.200419049

Cited by 11 publications

(13 citation statements)

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“…Fortunately, the mild and practical method of Ohira-Bestmann completed the task. [250][251][252] The aldehyde/acid mixture of 173 was reacted with the reagent 175 at 0 °C in the presence of potassium carbonate in methanol to produce the corresponding alkyne 174 (Scheme 13).…”

Section: Synthesis and Biological Evaluation Of Combretastatin A-1 Anmentioning

confidence: 99%

ortho-Formylation of oxygenated phenols

Akselsen

Skattebøl

Hansen

2009

Tetrahedron Letters

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Section: Synthesis and Biological Evaluation Of Combretastatin A-1 Anmentioning

confidence: 99%

ortho-Formylation of oxygenated phenols

Akselsen

Skattebøl

Hansen

2009

Tetrahedron Letters

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“…Horner–Wadsworth–Emmons reaction of 2c installed an α,β-unsaturated ester at the bridgehead 59 . Seyferth–Gilbert homolygation using the modified Bestmann's condition generated an alkyne functionality at the [3.1.0] bridgehead 60 . Epoxidation using trimethyl sulfonium iodide afforded 9c as a mixture of diastereomers 61 .…”

Section: Resultsmentioning

confidence: 99%

Asymmetric intramolecular α-cyclopropanation of aldehydes using a donor/acceptor carbene mimetic

2015

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Enantioselective α-alkylation of carbonyl is considered as one of the most important processes for asymmetric synthesis. Common alkylation agents, that is, alkyl halides, are notorious substrates for both Lewis acids and organocatalysts. Recently, olefins emerged as a benign alkylating species via photo/radical mechanisms. However, examples of enantioselective alkylation of aldehydes/ketones are scarce and direct asymmetric dialkylation remains elusive. Here we report an intramolecular α-cyclopropanation reaction of olefinic aldehydes to form chiral cyclopropane aldehydes. We demonstrate that an α-iodo aldehyde can function as a donor/acceptor carbene equivalent, which engages in a formal [2+1] annulation with a tethered double bond. Privileged bicyclo[3.1.0]hexane-type scaffolds are prepared in good optical purity using a chiral amine. The synthetic utility of the products is demonstrated by versatile transformations of the bridgehead formyl functionality. We expect the concept of using α-iodo iminium as a donor/acceptor carbene surrogate will find wide applications in chemical reaction development.

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“…The alcohol 9 was oxidized with IBX produced aldehyde, which on subsequent treatment with Bestmann's reagent resulted alkyne 16 in good yield [17][18][19]. The alkyne 16 was further treated with tributyltin hydride and catalytic AIBN, provided vinyl stannane derivative, the silyl group was subsequently deprotected by TBAF, THF produced compound 7 with excellent yield (Scheme 4).…”

Section: Synthesis Of Segmentmentioning

confidence: 99%

Synthesis of Key Fragments of 19-Membered Cytotoxic Macrolide Amphidinolide E

Mohapatra¹,

Nayak²,

Mishra³

et al. 2013

Letters in Organic Chemistry

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Amphidinolide E is a 19-membered macrolide possessing potent cytoxic activity. The macrolide core having two key intermediates alcohol and acid was synthesized efficiently. The THF ring segment was synthesized from Dglucose as chiral precursor, whereas the cis-tetrahydrofuran ring was established by stereoselective intramolecular oxymercuration reaction. The acid component having E-diene was established by Stille cross coupling of vinyl iodo and vinly stannane segment. Coupling reaction of acid segment and alcohol was examined.

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Further Improvements of the Synthesis of Alkynes from Aldehydes.

Cited by 11 publications

References 1 publication

ortho-Formylation of oxygenated phenols

ortho-Formylation of oxygenated phenols

Asymmetric intramolecular α-cyclopropanation of aldehydes using a donor/acceptor carbene mimetic

Synthesis of Key Fragments of 19-Membered Cytotoxic Macrolide Amphidinolide E

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