Highly Efficient Addition of Activated Methylene Compounds to Alkenes Catalyzed by Gold and Silver

Yao, Xiaoquan; Li, Chao‐Jun

doi:10.1021/ja0482637

Cited by 229 publications

(87 citation statements)

References 24 publications

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“…[11] Recently, a mixed catalyst system composed of 5 mol % AuCl 3 and 7.5 mol % AgOTf has also been employed for the direct addition of acetylacetone to styrene, which gave 89 % of 3-(1-phenylethyl)-pentane-2,4-dione at room temperature. [12] Moreover, solid acid catalysts have been described for this addition reaction. [13] For our investigations, the reaction of methyl 3-oxobutanoate (1) with 1-phenylethanol (2a) was studied as a model system (Scheme 2).…”

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confidence: 99%

A General and Efficient Iron‐Catalyzed Benzylation of 1,3‐Dicarbonyl Compounds

et al. 2007

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Various CH-acidic 1,3-dicarbonyl compounds and methyl 3-acetamidobut-2-enoate react with benzylic alcohols to give the corresponding 2-benzylated products in good to excellent yield. Typically, reactions proceed under mild conditions (50-80 8C; air) in the presence of catalytic amounts of inexpensive iron chloride hexahydrate. The benzylation of 4-hydroxycoumarin gives the pharmaceutically interesting 4-hydroxy-3-(1-phenylethyl)-2H-chromen-2-ones. As an example the anticoagulant Phenprocoumon is prepared in one step from commercially available substrates in 94 % yield.

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A General and Efficient Iron‐Catalyzed Benzylation of 1,3‐Dicarbonyl Compounds

et al. 2007

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Scandium-Catalyzed Propargylation of 1,3-Diketones with Propargyl Alcohols Bearing Sulfur or Selenium Functional Groups: Useful Transformation to Furans and Pyrans

Ohta

Kobayashi

Tanabe

et al. 2010

CHEMICAL & PHARMACEUTICAL BULLETIN

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Alkynyl and allenyl ketones have been widely used to form substituted furans and pyrans by methods such as acidmediated [1][2][3][4][5][6][7][8][9][10][11] and metal-catalyzed [12][13][14][15][16][17][18][19][20] cyclizations. Because of the wide utility of these furans and pyrans as building blocks for natural products and pharmaceuticals, 21,22) extending the list of ketones starting materials known to be suitable for their creation is important. Useful examples of the synthesis of propargylated ketones exist, [23][24][25][26] but it is questionable whether the ketones obtained are indeed practical for the synthesis of furans and pyrans. [27][28][29] Recently, we developed a method for highly regioselective C-C bond formation using propargyl alcohols with nucleophiles catalyzed by scandium triflate in MeNO 2 . 30,31) This unique reaction is achieved via the two-phase condition, and is effectively stabilized by a-sulfanyl and a-selanyl functional groups. During our on going study of catalytic reactions, we investigated in the formation of C-C bonds in propargyl alcohols with 1,3-diketones and their base-promoted transformations to heterocycles. In this article, we describe the formation of propargylated 1,3-diketones by Lewis-acid catalytic reactions, which easily yield furans and benzofurans under basic conditions. Results and DiscussionFirst, we prepared the propargylated 1,3-diketones via our original method that uses sulfur-substituted propargyl alcohol 1a with 1,3-diphenylpropanedione under the optimized conditions of 5 mol% scandium triflate, 10 mol% Bu 4 NHSO 4 , MeNO 2 -H 2 O (10 : 1). The reaction was completed within 10 min and the product was obtained as 2-benzoyl-3-(pmethoxyphenyl)-1-phenyl-5-(phenylsulfanyl)pent-4-yn-1-one (2a) in 77% yield. The structure of 2a was determined from its spectral features, which consist of the acetylenic infrared absorption at 2189 cm Ϫ1 and a pair of doublets at 5.16 and 5.86 (Jϭ10 Hz) in the 1 H-NMR spectra, and a molecular ion peak at m/z 476 (C 31 H 24 O 3 S) in the mass spectrum. This result indicates that 1,3-diketone was added to the propargyl cation, not the allenic cation. We next investigated reactions of propargyl alcohols with other 1,3-diketones and similar analogs, and the results are shown in Table 1. The reaction of 1a with 2,4-pentanedione gave the product 2b in 47% yield (entry 2); however, the reaction of 1a with ethyl acetoacetate gave rise to a complex mixture (entry 3). We also explored the reactions of the propargyl alcohols bearing a variety of aromatic groups at the a-position of the hydroxyl group, as shown in entries 4 and 5. In addition, we found that the selenium-substituted propargyl alcohols 1e-j also gave the adducts 2e-j in high yields (entries 6-11 of Table 1). However, the reactions of both 1,3-cyclohexanedione and cyclopentanedione gave 6,7-dihydro-5H-cyclohexa[b]pyran-5-one 3k, l and the cyclopentane derivative 3n, respectively, not the propanediones (entries 12, 13, 15 of Table 1). 32,33) The reaction of 2-methyl-1,3-hexanedione g...

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“…[14][15][16][17][18][19] Unlike many transition metal catalyzed reactions, gold catalysis does not require anhydrous and air free conditions.…”

Section: -13mentioning

confidence: 99%

“…[68][69][70][71][72][73][74] In most gold catalyzed reactions, catalyst loadings in the 1-5% range are the norm. [14][15][16][17][18] One reason for the low turnover numbers (TON) is the relatively fast decay of cationic gold and its conversion into non-reactive species (e.g., Au [75][76][77][78][79] Despite this drawback, there has been no comprehensive systematic investigations on the decay of homogeneous gold catalysis, a stark contrast with the extensive work reported on catalyst deactivation in heterogeneous catalysis. 80 In this chapter, we answer some fundamental and intriguing questions on gold(I) decay, such as the effects of starting material, nucleophile, solvent, counterion and additives, and we offer a probable pathway for gold(I) decay.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic insights and functionalization of alkynes in homogeneous gold catalysis.

Kumar¹

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Highly Efficient Addition of Activated Methylene Compounds to Alkenes Catalyzed by Gold and Silver

Abstract: A highly efficient intermolecular addition of 1,3-diketones to alkenes catalyzed by AuCl3/AgOTf was developed. A mechanistic rationale for the reaction has been proposed via a alpha-C-H activation.

Cited by 229 publications

References 24 publications

A General and Efficient Iron‐Catalyzed Benzylation of 1,3‐Dicarbonyl Compounds

A General and Efficient Iron‐Catalyzed Benzylation of 1,3‐Dicarbonyl Compounds

Scandium-Catalyzed Propargylation of 1,3-Diketones with Propargyl Alcohols Bearing Sulfur or Selenium Functional Groups: Useful Transformation to Furans and Pyrans

Mechanistic insights and functionalization of alkynes in homogeneous gold catalysis.

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