Ethyl 5‐Chloro‐3‐Phenylindole‐2‐Carboxylate

Fürstner, Alois; Hupperts, Achim; Seidel, Günter

doi:10.1002/0471264180.os076.14

Cited by 5 publications

(4 citation statements)

References 11 publications

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“…Previous investigations from this laboratory had shown that ketoamides, on treatment with “low-valent” titanium, convert to indole derivatives even in the presence of other reducible sites. , This reaction is best performed with titanium on graphite prepared from TiCl 3 and KC 8 (2 equiv) as the reagent, although other sources of low-valent titanium also provide good to excellent results in many cases . Such intramolecular reductive coupling reactions are distinguished by an exceptional driving force and a remarkable chemoselectivity profile, which allows for applications even to fairly elaborate cases. − …”

Section: Resultsmentioning

confidence: 99%

Total Syntheses of the Telomerase Inhibitors Dictyodendrin B, C, and E

2006

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Concise and flexible total syntheses of the pyrrolo[2,3-c]carbazole alkaloids dictyodendrin B (2), C (3), and E (5) are described. These polycyclic telomerase inhibitors of marine origin derive from the common intermediate 18 which was prepared on a multigram scale by a sequence comprising a TosMIC cycloaddition with formation of the pyrrole A-ring, a titanium-induced reductive oxoamide coupling reaction to generate an adjacent indole nucleus, and a photochemical 6pi-electrocyclization/aromatization tandem to forge the pyrrolocarbazole core. Conversion of 18 into dictyodendrin C required selective manipulations of the lateral protecting groups and oxidation with peroxoimidic acid to form the vinylogous benzoquinone core of the target. Zinc-induced reductive cleavage of the trichloroethyl sulfate ester then completed the first total synthesis of 3. Its relatives 2 and 5 also originate from compound 18 by a selective bromination of the pyrrole entity followed by elaboration of the resulting bromide 27 via metal-halogen exchange or cross-coupling chemistry, respectively. Particularly noteworthy in this context is the generation of the very labile p-quinomethide motif of dictyodendrin E by a palladium-catalyzed benzyl cross-coupling reaction followed by vinylogous oxidation of the resulting product 41 with DDQ. The Suzuki step could only be achieved with the aid of the borate complex 40 formed in situ from p-methoxybenzylmagnesium chloride and 9-MeO-9-BBN, whereas alternative methods employing benzylic boronates, -trifluoroborates, or -stannanes met with failure.

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Section: Resultsmentioning

confidence: 99%

Total Syntheses of the Telomerase Inhibitors Dictyodendrin B, C, and E

2006

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“…The addition of chlorotrimethylsilane liberated Cp 2 TiCl 2 from the product. This use of silyl chlorides to enable catalyst turnover had earlier been introduced by Fürstner for the TiCl 3 -catalyzed synthesis of indole, 30 and was also used in pinacol couplings. 12b Imidazole as an additive was suggested to prevent subsequent elimination of the tertiary alcohol.…”

Section: Ketone-nitrile Couplingsmentioning

confidence: 99%

Reductive Umpolung and Defunctionalization Reactions through Higher-Order Titanium(III) Catalysis

Streuff¹

2022

Synlett

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The single-electron transfer from an in situ formed titanium(III) catalyst to ketones, imines, nitriles, Michael acceptors, and many other functions has enabled a large number of intra- and intermolecular reductive umpolung reactions. Likewise, it allows the homolytic cleavage of functional groups for selective defunctionalizations. These reactions often take place with the participation of two titanium(III) species, avoiding free-radical pathways and enabling high catalyst control of the reaction selectivity. This account discusses the development of the individual reactions together with the fundamental mechanistic discoveries that led to a better understanding of such titanium(III)-catalyzed processes in general.1 Introduction2 Active Titanium(III) Species and Additives3 Ketone-Nitrile Couplings4 Further Reductive Umpolung Reactions5 Catalytic Homolytic C–CN and C–SO2R Cleavage6 Conclusion

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“…Thus the cyclisation of o-acylamino-or acyloxy-substituted benzophenones yields various indole and benzofuran derivatives. 202 The use of the McMurry reaction in the synthesis of substituted furans 284 and indoles 285 from compounds 286 and 287 has been described by Furstner et al 203,204 b. The Tebbe reaction In 1978, Tebbe et al 205 proposed to use metallacyclobutane 288 as a C 1 -synthon, which became a popular reagent for olefination of carbonyl compounds.…”

Section: Reagents Based On Group Ivb Metals a The Mcmurry Reactionmentioning

confidence: 99%

Olefination of carbonyl compounds: modern and classical methods

Korotchenko¹,

Nenajdenko²,

Баленкова³

et al. 2004

Russ. Chem. Rev.

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The published data on the methods for alkene synthesis The published data on the methods for alkene synthesis by olefination of carbonyl compounds are generalised and sys-by olefination of carbonyl compounds are generalised and systematised. The main attention is given to the use of transition tematised. The main attention is given to the use of transition metals and organoelement compounds. The review covers the metals and organoelement compounds. The review covers the data on both classical and newly developed methods that are little data on both classical and newly developed methods that are little known to chemists at large. The bibliography includes 276 known to chemists at large. The bibliography includes 276 references references. .

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Ethyl 5‐Chloro‐3‐Phenylindole‐2‐Carboxylate

Abstract: Ethyl 5‐chloro‐3‐phenylindole‐2‐carboxylate intermediate: N‐(2‐benzoyl‐4‐chlorophenyl)oxalamic acid ethyl ester product: ethyl 5‐chloro‐3‐phenylindole‐2‐carboxylate

Cited by 5 publications

References 11 publications

Total Syntheses of the Telomerase Inhibitors Dictyodendrin B, C, and E

Total Syntheses of the Telomerase Inhibitors Dictyodendrin B, C, and E

Reductive Umpolung and Defunctionalization Reactions through Higher-Order Titanium(III) Catalysis

Olefination of carbonyl compounds: modern and classical methods

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