Toward understanding the scope of Baylis–Hillman reaction: synthesis of 3-(2- hydroxyphenyl)indolin-2-ones and polycyclic fused furans

Basavaiah, Deevi; Roy, Suparna; Das, Utpal

doi:10.1016/j.tet.2010.05.087

Cited by 31 publications

(21 citation statements)

References 68 publications

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“…This is an example of halogen bonding [17,18], more generally known as σ-hole bonding. This is a common feature in the crystal structure of compounds containing the larger halogens, and has its origins in the attraction between various Lewis Base donors and the positive electrostatic regions at the terminus of a C-Halogen bond [19][20][21][22][23][24]. …”

Section: Resultsmentioning

confidence: 99%

Simple and Efficient One-Pot Synthesis, Spectroscopic Characterization and Crystal Structure of Methyl 5-(4-Chlorobenzoyloxy)-1-phenyl-1H-pyrazole-3-carboxylate

Khan

White

2012

Crystals

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A facile one-pot synthesis of methyl 5-(4-chlorobenzoyloxy)-1-phenyl-1H-pyrazole-3-carboxylate (4) is described. The title compound was efficiently synthesized by the reaction of phenyl hydrazine, dimethyl acetylenedicarboxylate and 4-chlorobenzoyl chloride in dichloromethane under reflux in good yield. The structure of the target compound was deduced by modern spectroscopic and analytical techniques and unequivocally confirmed by a single crystal X-ray diffraction analysis. The crystal of the title compound belongs to orthorhombic system, space group P 2 1 2 1 2 1 with cell parameters a = 6.6491(3) Å, b = 7.9627(6) Å, c = 30.621(5) Å, α = β = γ = 90° and Z = 4. The crystal packing of the compound (4) is stabilized by an offset π-stacking between the planar benzoyl-substituted diazole moieties.

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Section: Resultsmentioning

confidence: 99%

Simple and Efficient One-Pot Synthesis, Spectroscopic Characterization and Crystal Structure of Methyl 5-(4-Chlorobenzoyloxy)-1-phenyl-1H-pyrazole-3-carboxylate

Khan

White

2012

Crystals

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“…Finally, in a preliminary evaluation of the utility of the coupling products, adducts 3 b , 3 e , 3 j , 3 o , 3 q , and 3 t were exposed to catalytic amounts of p ‐toluenesulfonic acid in m ‐xylene at 80 °C. Cyclodehydration to form the corresponding substituted furans 4 a – 4 f occurred in good yields (Scheme ) 15 …”

Section: Methodsmentioning

confidence: 99%

Redox‐Triggered CC Coupling of Diols and Alkynes: Synthesis of β,γ‐Unsaturated α‐Hydroxyketones and Furans by Ruthenium‐Catalyzed Hydrohydroxyalkylation

2014

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Direct ruthenium‐catalyzed CC coupling of alkynes and vicinal diols to form β,γ‐unsaturated ketones occurs with complete levels of regioselectivity and good to complete control over the alkene geometry. Exposure of the reaction products to substoichiometric quantities of p‐toluenesulfonic acid induces cyclodehydration to form tetrasubstituted furans. These alkyne‐diol hydrohydroxyalkylations contribute to a growing body of merged redox‐construction events that bypass the use of premetalated reagents and, hence, stoichiometric quantities of metallic by‐products.

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“…14 Here, we report that the ruthenium(0) catalyst formed in situ from [Ru 3 (CO) 12 ] and tricyclohexylphosphine (PCy 3 ) promotes regio‐ and stereoselective alkyne‐diol hydrohydroxyalkylation to form α‐hydroxy‐β,γ‐unsaturated ketones in good to excellent yields (Scheme ). The reaction products engage in acid‐catalyzed cyclodehydration to form tetrasubstituted furans 15…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Redox‐Triggered CC Coupling of Diols and Alkynes: Synthesis of β,γ‐Unsaturated α‐Hydroxyketones and Furans by Ruthenium‐Catalyzed Hydrohydroxyalkylation

2014

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Direct ruthenium-catalyzed C À C coupling of alkynes and vicinal diols to form b,g-unsaturated ketones occurs with complete levels of regioselectivity and good to complete control over the alkene geometry. Exposure of the reaction products to substoichiometric quantities of p-toluenesulfonic acid induces cyclodehydration to form tetrasubstituted furans. These alkyne-diol hydrohydroxyalkylations contribute to a growing body of merged redox-construction events that bypass the use of premetalated reagents and, hence, stoichiometric quantities of metallic by-products.Metal-catalyzed reductive coupling reactions of p-unsaturated reactants bypass the use of premetalated C-nucleophiles in a range of carbonyl and imine additions.[1] Despite significant advances, catalytic intermolecular reductive coupling reactions of simple alkenes or alkynes to ketones (activated or unactivated) remain uncommon. [2][3][4][5][6][7] In connection with efforts aimed at the development of hydrogenmediated reductive coupling reactions beyond hydroformylation, [1f,g,h] rhodium-or iridium-catalyzed hydrogenations of a-ketoesters in the presence of conjugated or nonconjugated alkynes were found to promote the formation of a-hydroxyesters (Scheme 1). [6b,c, 7] More recently, under the conditions of ruthenium(0)-catalyzed transfer hydrogenation, it was found that activated secondary alcohols engage in C À C coupling to unsaturated reactants to form products of hydrohydroxyalkylation. [8][9][10][11] Specifically, the catalytic CÀC coupling of a-hydroxy carbonyl compounds [8] or 1,2-diols [8d,f] with conjugated dienes, [8a,b,d,e] terminal olefins, [8c] and a,b-unsaturated esters [8f] was achieved. The feasibility of coupling secondary alcohols to alkynes [6,7,9,12] under the conditions of ruthenium(0)-catalyzed transfer hydrogenation was unclear, as ruthenium(0) complexes are efficient catalysts for alkyne [2+2+2] cycloaddition. [13,14] Here, we report that the ruthenium(0) catalyst formed in situ from [Ru 3 (CO) 12 ] and tricyclohexylphosphine (PCy 3 ) promotes regio-and stereoselective alkyne-diol hydrohydroxyalkylation to form a-hydroxyb,g-unsaturated ketones in good to excellent yields (Scheme 1). The reaction products engage in acid-catalyzed cyclodehydration to form tetrasubstituted furans. [15] In a preliminary experiment, racemic trans-1,2-cyclohexane diol (1 b) was exposed to 1-phenyl-1-propyne (2 a) under conditions established for the CÀC coupling of dienes to ahydroxy esters or a-hydroxy amides. [8a,b] The anticipated product of hydrohydroxyalkylation 3 b was formed, but in only 14 % yield [Eq. (1)]. In related rhodium-or iridiumcatalyzed alkyne-a-ketoester reductive coupling reactions using elemental hydrogen as the terminal reductant, [6b,c, 7] carboxylic acid co-catalysts were found to increase the rate and conversion. As supported by computational studies, [16] such acid co-catalysts bypass highly energetic four-centered transition structures for the direct hydrogenolysis of oxametallacyclic intermediates through...

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Toward understanding the scope of Baylis–Hillman reaction: synthesis of 3-(2- hydroxyphenyl)indolin-2-ones and polycyclic fused furans

Cited by 31 publications

References 68 publications

Simple and Efficient One-Pot Synthesis, Spectroscopic Characterization and Crystal Structure of Methyl 5-(4-Chlorobenzoyloxy)-1-phenyl-1H-pyrazole-3-carboxylate

Simple and Efficient One-Pot Synthesis, Spectroscopic Characterization and Crystal Structure of Methyl 5-(4-Chlorobenzoyloxy)-1-phenyl-1H-pyrazole-3-carboxylate

Redox‐Triggered CC Coupling of Diols and Alkynes: Synthesis of β,γ‐Unsaturated α‐Hydroxyketones and Furans by Ruthenium‐Catalyzed Hydrohydroxyalkylation

Redox‐Triggered CC Coupling of Diols and Alkynes: Synthesis of β,γ‐Unsaturated α‐Hydroxyketones and Furans by Ruthenium‐Catalyzed Hydrohydroxyalkylation

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