Allylic alcohols: Valuable synthetic equivalents of non-activated alkenes in gold-catalyzed enantioselective alkylation of indoles

Bandini, Marco; Gualandi, Andrea; Monari, Magda; Romaniello, Alessandro; Savoia, Diego; Tragni, Michele

doi:10.1016/j.jorganchem.2010.09.065

Cited by 58 publications

(19 citation statements)

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“…[64][65][66] [L16(AuOTf) 2 ] was used as the active catalyst precursor for these reactions. Bandini and co-workers developed a gold-catalyzed enantioselective allylic alkylation of indoles with allylic alcohols utilising (R)-DTBM-MeObiphep ligand L16.…”

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confidence: 99%

Transition metal-catalyzed allylic substitution reactions with unactivated allylic substrates

2015

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The transition metal-catalyzed allylic substitution of unactivated allylic substrates (allylic alcohols, allylic ethers and allylic amines) is rapidly becoming an important area of research. There are several advantages to using these substrates in allylic substitution reactions: the use of unactivated alcohols minimizes the production of waste by-products and reaction steps; and allylic ethers and allylic amines are useful substrates because of their stability and their presence in numerous biologically active compounds. Research in this field has therefore gained widespread attention for promoting the development of efficient and environmentally benign procedures for the formation of C-C, C-N and C-O bonds.

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Section: View Article Onlinementioning

confidence: 99%

Transition metal-catalyzed allylic substitution reactions with unactivated allylic substrates

2015

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“…[84][85][86] Valuable alkaloid precursors could be obtained in high yield and enantiomeric excess by this methodology, by conducting the reaction in the presence of a chiral binuclear gold(I) catalyst. [84][85][86] Valuable alkaloid precursors could be obtained in high yield and enantiomeric excess by this methodology, by conducting the reaction in the presence of a chiral binuclear gold(I) catalyst.…”

Section: Reactions With C Sp 3 Alkylating Agentsmentioning

confidence: 99%

Gold‐Catalyzed Functionalization Reactions of Indole

Pirovano

2018

Eur J Org Chem

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This review summarizes the progress achieved in the last fifteen years by application of homogeneous gold catalysis in the field of indole functionalization. Several electrophilic species obtained through gold‐catalyzed π‐activation have in fact been found to react with the nucleophilic positions of indole, thus allowing its efficient manipulation. In order to furnish a complete and clear overview on the role of the catalyst, the review is organized from the perspective of the gold‐activated substrate that is reacting with the indole. In addition, in view of the ability of gold to catalyze tandem and cascade reactions, a separate section describes tandem/cascade protocols useful for the synthesis of complex polycyclic indole derivatives. Finally, gold catalysis has also been employed for the synthesis of indole‐based natural products. For this reason, a dedicated section collects all the work in which the key step to obtain these complex indoles is represented by a gold‐catalyzed reaction.

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“…The methodology worked well for both C2‐ and C3‐alkylation of the indolyl core, delivering enantiomerically enriched 1‐vinyl tetrahydrocarbazoles 266 and 4‐vinyl tetrahydrocarbazoles 269 , respectively. Analogously, chiral tetrahydro‐β‐carboline 271 could also be synthesized through this procedure (Scheme ) . In sharp contrast to the high activity of the N1 ‐unprotected C3‐substituted indolyl alcohols 265 , their N1 ‐methyl‐substituted analogue 267 did not participated at all in the Friedel–Crafts‐type cyclization but was recovered in up to 80 % yield.…”

Section: Cyclization Of C−c Multiple Bonds With Tethered Nucleophilesmentioning

confidence: 99%

Gold‐Catalyzed Enantioselective Annulations

Zhang

2016

Chemistry A European J

221

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Non-oxidative,regioselective,and convergent access to densely functionalized oxazoles is realized in af unctional-group tolerant manner using alkynyl thioethers.S ulfur-terminated alkynes provideaccess to reactivity previously requiring strong donor-substituted alkynes such as ynamides.Sulfur does not act in an analogous donor fashion in this gold-catalyzed reaction, thus leading to complementary regioselective outcomes and addressing the limitations of using ynamides. Compared to other heteroatom-substituted alkynes,alkynyl thioethers are remarkably little explored in intermolecular late-transition-metal catalysis,d espite being readily accessed and robust. [1, 2] Ynamides,i nc ontrast, are privileged sub-strates:i np-acid catalysis their donor nature aids metal-alkyne coordination and affords highly polarized electro-philes,t hus providing the high chemo-and regioselectivity required for the discovery of efficient intermolecular reactions (Scheme 1a). [3,4] As the resulting inclusion of ad onor-nitrogen atom limits the utility of the products,r etaining the reactivity profile of these transformations whilst accessing more flexible and readily elaborated substitution patterns would be desirable.T he value of sulfur-substituted compounds [5] coupled with progress in C À Ca nd C-heteroatom bond formation from CÀSbonds, [6] renders alkynyl thioethers appealing alternatives to ynamides.I ndeed the ketenethio-nium pathway (Scheme 1a)f rom alkynyl thioethers has recently been invoked in proton-catalyzed reactions with nitriles [2g,h] and gold-catalyzed reactions with sulfides. [2i] Ynamides enabled the discovery of formal [3+ +2] dipolar cycloadditions with nucleophilic nitrenoids, [7] thus allowing intermolecular access to a-imino gold carbene-type reactivity for heterocycle synthesis (Scheme 1b). [8, 9] Such reactions, which do not depend on ynamides,a re scarce. [8b,h] As trong donor alkyne substituent proved critical in the formation of oxazoles using N-acyl pyridinium N-aminides,aselectron-rich alkynes such as anisole derivatives did not react (Scheme 1b, inset). [8a,b] Oxazoles are valuable synthetic intermediates [10,11] and structural components in bioactive natural products, [12] agrochemicals, [13] ligands, [14] and functional materials. [15] Despite recent advances,asingle modular and convergent route to trisubstituted oxazoles,which provides the structural and functional-group diversity needed across the 2-, 4-, and 5-positions,r emains unrealized. [16] Following our interest in the use of gold catalysis with sulfides [17] we report here on the reactivity of alkynyl thioethers with nucleophilic nitrenoids to prepare oxazoles. Importantly,t he regioselectivity is not consistent with ac on-trolling ketenethionium species.T he sulfur group plays an alternative role in enabling reactivity,t hus proving complementary to donor-enabled approaches. Ther eaction of the alkynyl thioether 1a and aminide 2a (Table 1) showed that conversion into the oxazole 3 was possible at 125 8 8Ci n1 ,2-dichlorobenzene (1,2-DCB;s ...

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Allylic alcohols: Valuable synthetic equivalents of non-activated alkenes in gold-catalyzed enantioselective alkylation of indoles

Cited by 58 publications

References 46 publications

Transition metal-catalyzed allylic substitution reactions with unactivated allylic substrates

Transition metal-catalyzed allylic substitution reactions with unactivated allylic substrates

Gold‐Catalyzed Functionalization Reactions of Indole

Gold‐Catalyzed Enantioselective Annulations

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