Synthesis of isotetronic acids by cyclization of 1,3-bis(trimethylsilyloxy)alk-1-enes with oxalyl chloride

Dede, Rüdiger; Michaelis, Lars; Langer, Peter

doi:10.1016/j.tetlet.2005.09.137

Cited by 20 publications

(10 citation statements)

References 39 publications

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“…These functionalized dihydrofurans are promising candidates for drug design because the dihydrofuran structure is intrinsic for a number of natural (ascorbic and penicillin acids, derivatives of tetronic acid), and biologically active products (azadirachtin, clerodin, austocystin A, etc. ), [18,19] some of which show antibacterial, antifungicidal, [20] antiviral, [21] and antiAIDS properties. [21,22] Thus, the results contribute both to basic benzimidazole chemistry and provide a new prospective family of drug candidates.…”

Section: Discussionmentioning

confidence: 99%

Annelation of Benzimidazoles with α,β‐Acetylenic γ‐Hydroxyacid Nitriles and Hydrolytic Rearrangement of the Cycloadducts on Alumina

et al. 2007

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Abstract1‐Substituted benzimidazoles are readily annelated regio‐ and stereoselectively with α,β‐acetylenic γ‐hydroxyacidnitriles under mild conditions (20–25 °C, no catalyst, no solvent) to form new polyfunctional condensed systems, 4‐cyanomethylene‐1,3‐oxazolobenzimidazoles (30–88 % yield). Unexpectedly, the latter, when chromatographed on neutral Al2O3 at room temperature, undergo a complex multi‐position hydrolytic rearrangement involving the cleavage of the imidazole ring to aminophenyl N‐substituted formamides with an aminodihydrofuran moiety in the aminophenylsubstituent, N‐(2‐{[5‐amino‐2,2‐dialkyl‐3(2H)‐furanylidene]amino}phenyl)‐N‐substituted formamides, a novel class of highly functionalized pharmacophoric compounds. The results contribute to the basic benzimidazole chemistry and provide for prospective families of drug candidates.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

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Section: Discussionmentioning

confidence: 99%

Annelation of Benzimidazoles with α,β‐Acetylenic γ‐Hydroxyacid Nitriles and Hydrolytic Rearrangement of the Cycloadducts on Alumina

et al. 2007

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“…The best results were obtained when the reaction was carried out without the presence of a Lewis acid. 16 Employment of enantiomerically pure 1,3-bis(trimethylsilyloxy)alk-1-enes results in the formation of enantiomerically pure butenolides. The hydroxy group could be functionalized by Suzuki reactions of the corresponding enol triflates.…”

Section: 3-bis(trimethylsilyloxy)alk-1-enesmentioning

confidence: 99%

Synthesis of Butenolides by One-Pot Cyclization Reactions of Silyl Enol Ethers with Oxalyl Chloride

Langer¹

2006

Synlett

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Oxalyl chloride represents a versatile C 2 building block for cyclization reactions. A variety of cyclization reactions of oxalyl chloride are known which involve the formation of two carbon-heteroatom bonds. In contrast, one-pot cyclizations of oxalyl derivatives which proceed by formation of at least one carbon-carbon bond are more rare. In recent years, a number of such cyclizations have been developed which rely on the reaction of oxalyl chloride with silyl enol ethers. These reactions allow for an efficient synthesis of various oxygen heterocycles, such as g-alkylidenebutenolides, maleic anhydrides and isotetronic acids. The cyclization reactions, which involve the formation of a carbon-carbon and a carbon-oxygen bond, generally proceed with excellent regioselectivity.

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“…[8][9][10][11][12][13][14] Based on retrosynthetic analysis, homoaldol condensation of 2-oxocarboxylic esters and subsequent lactonization of the adduct would be a straightforward way to isotetronic acids. García-Tellado and coworker has devised a novel ABB' three-component reaction system based on triethylamine catalyzed homoaldol reaction of α-ketoesters in the presence of terminal conjugated alkynoates.…”

Section: Introductionmentioning

confidence: 99%

Approach to novel isotetronic acid derivatives: DBU-Et3N-mediated aldol/lactonization/O-protection sequence of 2-oxocarboxylic esters

Chen¹,

Ma²,

Li³

et al. 2009

Arkivoc

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An efficient synthesis of novel O-protected isotetronic acids is described. The method relies on DBU (1,8-diazabicyclo[5.4.0]-undec-7-ene) and triethylamine triggered homo-aldol reactions of 2-oxocarboxylic esters, followed by successful ring closure via lactonization and O-protection with various electrophiles. The unprotected isotetronic acids were also achieved with moderate to high yields if the free-OH group were pre-capped by the silylation agent TMSCl. All the three reaction steps were conducted in a sequential manner, without isolation of any intermediates.

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Synthesis of isotetronic acids by cyclization of 1,3-bis(trimethylsilyloxy)alk-1-enes with oxalyl chloride

Cited by 20 publications

References 39 publications

Annelation of Benzimidazoles with α,β‐Acetylenic γ‐Hydroxyacid Nitriles and Hydrolytic Rearrangement of the Cycloadducts on Alumina

Annelation of Benzimidazoles with α,β‐Acetylenic γ‐Hydroxyacid Nitriles and Hydrolytic Rearrangement of the Cycloadducts on Alumina

Synthesis of Butenolides by One-Pot Cyclization Reactions of Silyl Enol Ethers with Oxalyl Chloride

Approach to novel isotetronic acid derivatives: DBU-Et3N-mediated aldol/lactonization/O-protection sequence of 2-oxocarboxylic esters

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