meso-Di(heteroaryl)methanes: versatile building blocks of porphyrinoids

Singh, Kamaljit; Sharma, Sunny; Kaur, Paramjit; Hee-Lee, Chang

doi:10.1016/j.tet.2015.06.108

Cited by 9 publications

(1 citation statement)

References 195 publications

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“…On the basis of these experimental results and, in addition, of the previous ones reported by us and others, plausible reaction mechanisms are depicted in Scheme , where α,α′-5 is omitted, due actually to the nonformation of α-4 derived inevitably from α,α ′ -5 . At first, the indium(III) Lewis acid ( In ), which will work as an activator of the CO bond of 6 , assembles 1 and 6 into dipyrrolylalkanes 5 , the formation of which is the well-known process most frequently promoted by a (Lewis) acid . The predominant generation of β,β′-5 over the other two isomers results from the highest thermodynamic stability, probably because of the least steric repulsion between the two R 1 groups (Scheme , (i)), as previously observed .…”

Section: Resultsmentioning

confidence: 99%

Indium-Catalyzed Regioselective β-Alkylation of Pyrroles with Carbonyl Compounds and Hydrosilanes and Its Application to Construction of a Quaternary Carbon Center with a β-Pyrrolyl Group

et al. 2017

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Treatment of N-substituted pyrroles with carbonyl compounds and nucleophiles under indium catalysis was found to be a promising method for preparing β-alkylpyrroles without contamination by α-alkylpyrroles. With this methodology, a variety of alkyl groups, which are primary, secondary, and tertiary as well as cyclic and functionalized types, can be introduced in place onto the pyrrole ring. The simplicity performable as a catalytic one-step process is one of the important features of this reaction. The substituent on the nitrogen atom of the product β-alkylpyrrole can be removed easily by literature procedures. Therefore, the indium-catalyzed β-alkylation plus the N-deprotection is a powerful system for all six variations, which are N-substituted and N-unsubstituted β-alkylpyrroles having primary, secondary, and tertiary alkyl groups. Our method is applicable to synthesizing, albeit in two steps, β-pyrrolyl-group-connected unsymmetrical tetraarylmethanes that have not been addressed thus far. Mechanistic studies showed the following three aspects: (1) dipyrrolylalkanes produced in situ from the pyrrole and carbonyl compound are key intermediates, (2) the selective β-alkylation is attributed to the selective elimination of an α-pyrrolyl group from the dipyrrolylalkane intermediates, and (3) the indium Lewis acid catalyst is indispensable for the progress of both stages.

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Section: Resultsmentioning

confidence: 99%

Indium-Catalyzed Regioselective β-Alkylation of Pyrroles with Carbonyl Compounds and Hydrosilanes and Its Application to Construction of a Quaternary Carbon Center with a β-Pyrrolyl Group

et al. 2017

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ChemInform Abstract: meso‐Di(heteroaryl)methanes: Versatile Building Blocks of Porphyrinoids

et al. 2015

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Imidazolium Zwitterionic Molten Salt: An Efficient Organocatalyst under Neat Conditions at Room Temperature for the Synthesis of Dipyrromethanes as well as Bis(indolyl)methanes

et al. 2018

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An imidazole-based zwitterionic-salt, 4-(3-methylimidazolium) butane sulfonate (MBS), has been found to be an efficient organocatalyst for the synthesis of dipyrromethanes as well as bis(indolyl)methanes at room temperature under solvent-free conditions (neat) in high yields. The reaction procedure is very simple and a large variety of aldehydes have been examined under similar conditions for indoles and pyrroles. The catalytic reaction proceeded very smoothly and showed high chemoselectivity. Clean reaction, ease of product isolation/purification, easily accessible reactants, metal and solvent-free and environmentally friendly reaction conditions are the notable advantages of the present methodology.

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meso-Di(heteroaryl)methanes: versatile building blocks of porphyrinoids

Cited by 9 publications

References 195 publications

Indium-Catalyzed Regioselective β-Alkylation of Pyrroles with Carbonyl Compounds and Hydrosilanes and Its Application to Construction of a Quaternary Carbon Center with a β-Pyrrolyl Group

Indium-Catalyzed Regioselective β-Alkylation of Pyrroles with Carbonyl Compounds and Hydrosilanes and Its Application to Construction of a Quaternary Carbon Center with a β-Pyrrolyl Group

ChemInform Abstract: meso‐Di(heteroaryl)methanes: Versatile Building Blocks of Porphyrinoids

Imidazolium Zwitterionic Molten Salt: An Efficient Organocatalyst under Neat Conditions at Room Temperature for the Synthesis of Dipyrromethanes as well as Bis(indolyl)methanes

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