Sodium Trimethylethynylaluminate, a New Chemoselective Ethynylating Agent

Joung, Meyoung Ju; Ahn, Jin Hee; Yoon, Nung Min

doi:10.1021/jo960123v

Cited by 20 publications

(8 citation statements)

References 17 publications

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“…Nevetheless, the role of ate complexes in this increased selectivity could not be established . Yoon and co-workers reported the chemoselective (in the presence of halide, epoxide, ester, amide, and nitrile functionalities) 1,2-alkynylation of aldehydes and ketones using either Na diethyldialkynylaluminate, prepared by adding 2 equiv of a terminal acetylene to Et 2 H 2 AlNa (Table ), or Na trimethylethynylaluminate, prepared from Me 3 Al and Na acetylide (Table ) …”

Section: Reactions Of Maas Involving Nucleophile Ligand Transfer Proc...mentioning

confidence: 99%

Mixed AggregAte (MAA): A Single Concept for All Dipolar Organometallic Aggregates. 2. Syntheses and Reactivities of Homo/HeteroMAAs

2013

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6. Conclusion 7706 Author Information 7706 Biographies 7707 Acknowledgment 7707 Abbreviations Used 7707 References 7708the corresponding allyl-and propargylchromium reagents that further react with a variety of electrophiles to afford the corresponding adducts in high yields. 102 Bu 6 CrLi 3 similarly behaves as a formal two-electron reductant with ketones and esters bearing a leaving group at the α-position to produce enolates that are intercepted with a variety of electrophiles with high selectivities (Table 8). 103 Such enolates are also capable of reacting with oxiranes to afford γand β-hydroxy esters, depending on the Lewis acid used as promoter. 2143.2.2. Two-Electron Transfers from M,Mn-HeteroMAAs (M = Li, MgX). In 1976, Cahiez et al. disclosed the possible reduction in THF of alkenyl bromides or iodides, as well as aryl chlorides or bromides, using i-PrMgCl in the presence of a catalytic amount of MnCl 2 . 215 The authors proposed the in situ formation of unstable i-Pr 3 MnMgCl and its decomposition by β-elimination to H 3 MnMgCl; reaction of the latter with the halide would then afford an unstable Mn(IV) intermediate, able Scheme 23 Scheme 24 Scheme 21 Scheme 22

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Section: Reactions Of Maas Involving Nucleophile Ligand Transfer Proc...mentioning

confidence: 99%

Mixed AggregAte (MAA): A Single Concept for All Dipolar Organometallic Aggregates. 2. Syntheses and Reactivities of Homo/HeteroMAAs

2013

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“…The hydroxyl aldehyde 7j was prepared following the general procedure A from bromo aldehyde (363 mg, 1.5 mmol), propargyl alcohol (183 mg, 1.5 mmol), anhydrous THF (13 mL), anhydrous i Pr 2 NH (3 mL), CuI (42 mg, 0.23 mmol), and Pd(PPh 3 ) 2 Cl 2 (10 mg, 0.015 mmol), by stirring for 17 h at room temperature. Purification by flash chromatography (4/1 hexane/EtOAc) gave the hydroxy aldehyde 7j (220 mg, 0.9 mmol, 60%) as a pale yellow oil.…”

Section: Methodsmentioning

confidence: 99%

Mild Approach to 2-Acylfurans via Intercepted Meyer–Schuster Rearrangement of 6-Hydroxyhex-2-en-4-ynals

Tharra

Baire

2015

J. Org. Chem.

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We have developed a mild, intramolecular intercepted Meyer-Schuster (M-S) rearrangement for the synthesis of 2-acylfurans from corresponding cis-6-hydroxyhex-2-en-4-ynals. This reaction was found to be very general, and the starting materials are easily accessible. By this methodology the first synthesis of deoxy-nor-abiesesquine B, a sesquiterpene, was also achieved in three steps. The concept of adding two nucleophiles during the M-S rearrangement was introduced.

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“…Since sodium acetylide is highly insoluble and seemingly too basic to be an effective nucleophile in our system, a way to modify its reactivity was sought. After some experimentation, we were delighted to find that sodium trimethylethynylaluminateformed by premixing equimolar amounts of sodium acetylide and trimethylaluminum in a mixture of THF and toluenewas a singularly effective acetylide source, giving the desired product in high yield and with better than 19:1 diastereoselectivity (Table , entry 4) …”

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confidence: 99%

Nine-Step Stereoselective Synthesis of Islatravir from Deoxyribose

et al. 2020

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A stereoselective nine-step synthesis of the potent HIV nucleoside reverse transcriptase translocation inhibitor (NRTTI) islatravir (EfdA, MK-8591) from 2-deoxyribose is described. Key findings include a diastereodivergent addition of an acetylide nucleophile to an enolizable ketone, a chemoselective ozonolysis of a terminal olefin and a biocatalytic glycosylation cascade that uses a unique strategy of byproduct precipitation to drive an otherwise-reversible transformation forward.

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Sodium Trimethylethynylaluminate, a New Chemoselective Ethynylating Agent

Cited by 20 publications

References 17 publications

Mixed AggregAte (MAA): A Single Concept for All Dipolar Organometallic Aggregates. 2. Syntheses and Reactivities of Homo/HeteroMAAs

Mixed AggregAte (MAA): A Single Concept for All Dipolar Organometallic Aggregates. 2. Syntheses and Reactivities of Homo/HeteroMAAs

Mild Approach to 2-Acylfurans via Intercepted Meyer–Schuster Rearrangement of 6-Hydroxyhex-2-en-4-ynals

Nine-Step Stereoselective Synthesis of Islatravir from Deoxyribose

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