Niobium(V) chloride-catalyzed C–H insertion reactions of α-diazoesters: synthesis of β-keto esters

Yadav, J. S.; Reddy, B. V. Subba; Eeshwaraiah, B.; Reddy, P. N.

doi:10.1016/j.tet.2004.11.027

Cited by 55 publications

(8 citation statements)

References 18 publications

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“…The carbon nucleophile attacks on the carbonyl group aldehyde and subsequent 1,2-hydride shift with loss of nitrogen resulting in the formation of the b-keto ester (Scheme 2). Such a mechanism was proposed earlier by Yadav et al 11 In conclusion, molybdenum(VI) dichloride dioxide was successfully used as catalyst for the synthesis of b-keto esters by condensing aldehydes with ethyl diazoacetate at room temperature. No side products were obtained during the condensation reactions.…”

supporting

confidence: 53%

Molybdenum(VI) Dichloride Dioxide Catalyzed Synthesis of β-Keto Esters by C-H Insertion of Ethyl Diazoacetate into Aldehydes

Kandasamy¹,

Chand²

2008

Synthesis

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supporting

confidence: 53%

Molybdenum(VI) Dichloride Dioxide Catalyzed Synthesis of β-Keto Esters by C-H Insertion of Ethyl Diazoacetate into Aldehydes

Kandasamy¹,

Chand²

2008

Synthesis

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“…[23] This opened the door for the anticipated asymmetric hydrogenation. [24] By using 1 mol-% of (R)-[{RuCl(tol-BINAP)} 2 (μ-Cl) 3 The installation of the long spacer of mycoside B was preceded by a four-step synthesis of building block 20, as depicted in Scheme 3.…”

Section: Resultsmentioning

confidence: 99%

Total Synthesis of the Phenolic Glycolipid Mycoside B and the Glycosylated p‐Hydroxybenzoic Acid Methyl Ester HBAD‐I, Virulence Markers of Mycobacterium tuberculosis

Barroso¹,

Geerdink²,

Horst³

et al. 2013

Eur J Org Chem

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The phenolic glycolipid mycoside B, present in Mycobacterium bovis and hypervirulent strains of Mycobacterium tuberculosis, has been synthesized for the first time. Multiple methyl groups were introduced by the extensive use of catalytic asymmetric 1,4‐addition reactions, asymmetric hydrogenation of a β‐keto ester afforded the basis for the central 1,3‐diol moiety, and introduction of the 2‐O‐methyl‐α‐L‐rhamnoside unit was achieved by stereoselective glycosylation with p‐iodophenol and subsequent Sonogashira coupling, providing a basis for the generation of analogues. In addition, the related monosaccharide HBAD‐I, present in the same species, has been efficiently synthesized for the first time by selective methylation of the hydroxy group at C‐2 of a rhamnoside.

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“…Efficient transformation of 15 into β‐ketoester 16 was achieved by treatment with ethyl diazoacetate employing NbCl 5 as catalyst 17. This transformation set the stage for the introduction of the third stereocenter.…”

Section: Methodsmentioning

confidence: 99%

Total Synthesis of the Triglycosyl Phenolic Glycolipid PGL‐tb1 from Mycobacterium tuberculosis

et al. 2012

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Mycobacterium tuberculosis (M. tb) is one of the most important pathogens. Despite the availability of antibiotics and a vaccine (BCG), one third of the worlds population is infected with M. tb, causing 8 million casualties and 1.5 million deaths yearly. [1] Synergy with HIV and the appearance of M. tb strains that are multi-drug resistant or hypervirulent, poses further threats. [2] The search for novel drugs and more effective vaccines entered a new era with the publication of the genome sequence of M. tb H37Rv. [3] Based on this sequence, genes that code for enzymes involved in the critical steps of hostpathogen interaction were identified. Many of these enzymes are involved in the synthesis and transport of complex lipids, in particular phthiocerol dimycocerosates (DIM [4] or PDIM [5] ) present in the outer layer of the M. tb cell envelope. Furthermore, several M. tb strains synthesize closely related phenolic glycolipids (PGL-tb1, Figure 1) in which the phthiocerol is connected to a glycosylated phenol. It has been shown that DIM/PDIMs are required for multiplication and persistence of M. tb in vivo. [6] Next to this, PGL-tb1 (1, Figure 1) is suspected to be involved in hypervirulence of specific M. tb strains. [7] The interplay of M. tb with the human host is very complex, with PGL-tb1 as one of the most unusual virulence factors modulating its defense systems and causing disease. Thus, there is a great need for antigens that permit to distinguish between prior BCG vaccination and infection.

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Niobium(V) chloride-catalyzed C–H insertion reactions of α-diazoesters: synthesis of β-keto esters

Cited by 55 publications

References 18 publications

Molybdenum(VI) Dichloride Dioxide Catalyzed Synthesis of β-Keto Esters by C-H Insertion of Ethyl Diazoacetate into Aldehydes

Molybdenum(VI) Dichloride Dioxide Catalyzed Synthesis of β-Keto Esters by C-H Insertion of Ethyl Diazoacetate into Aldehydes

Total Synthesis of the Phenolic Glycolipid Mycoside B and the Glycosylated p‐Hydroxybenzoic Acid Methyl Ester HBAD‐I, Virulence Markers of Mycobacterium tuberculosis

Total Synthesis of the Triglycosyl Phenolic Glycolipid PGL‐tb1 from Mycobacterium tuberculosis

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