- Cobalt-catalyzed acylation-reactions of (hetero)arylzinc pivalates with thiopyridyl ester derivatives
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A cobalt-catalyzed acylation reaction of various primary, secondary and tertiary alkyl, benzyl and (hetero)aryl S-pyridyl thioesters with (hetero)arylzinc pivalates is reported. The thioesters were prepared directly from the corresponding carboxylic acids under mild conditions, thus tolerating sensitive functional groups. Acylations of α-chiral S-pyridyl esters proceeded with very high stereoretention leading to optically enriched α-chiral ketones.
- Lutter, Ferdinand H.,Grokenberger, Lucie,Hofmayer, Maximilian S.,Knochel, Paul
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p. 8241 - 8245
(2019/09/19)
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- Facile synthesis of 1,9-diacyldipyrromethanes
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The present invention provides a method of making a metal complex. The method comprises the steps of: (a) acylating a dipyrromethane or a 1-monoacyldipyrromethane to form a mixed reaction product comprising a 1,9-diacyidipyrromethane; (b) combining the re
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Page/Page column 6; 15
(2010/02/11)
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- 9-Acylation of 1-acyldipyrromethanes containing a dialkylboron mask for the α-acylpyrrole motif
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1,9-Diacyldipyrromethanes are important precursors to porphyrins, yet synthetic access remains limited owing to (1) poor conversion in the 9-acylation of 1-acyldipyrromethanes and (2) handling difficulties because acyldipyrromethanes typically streak upon
- Zaidi, Syeda Huma H.,Muthukumaran, Kannan,Tamaru, Shun-Ichi,Lindsey, Jonathan S.
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p. 8356 - 8365
(2007/10/03)
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- Efficient synthesis of monoacyl dipyrromethanes and their use in the preparation of sterically unhindered trans-porphyrins
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The condensation of an aldehyde with a dipyrromethane bearing a sterically unhindered aryl substituent at the 5-position typically results in low yield and a mixture of porphyrin products derived from acidolytic scrambling. We have developed a concise nonscrambling synthesis of such trans-porphyrins that takes advantage of the availability of multigram quantities of dipyrromethanes. This route involves the selective monoacylation of the dipyrromethanes with a pyridyl thioester, reduction of the monoacyl dipyrromethane to the corresponding carbinol, and self- condensation of the carbinol to form the porphyrin. The monoacylation procedure has wide scope as demonstrated by the preparation of a set of 15 diverse monoacyl dipyrromethanes in good yield at the multigram scale. The dipyrromethanecarbinol self-condensation reaction is extremely rapid (3 min) under mild room-temperature conditions and affords the trans-porphyrin in 16- 28% yield. Analysis by laser-desorption mass spectrometry (LD-MS) of samples from the crude reaction mixture revealed no scrambling within the limit of detection (1 part in 100). The self-condensation is compatible with a range of electron-withdrawing or -releasing substituents as well as substituents for building block applications (TMS-ethyne, ethyne, iodo, ester). The absence of any detectable scrambling in the self-condensation enables a simple purification. The synthesis readily affords gram quantities of pure, sterically unhindered trans-porphyrins in a process involving minimal chromatography.
- Rao, Polisetti Dharma,Littler, Benjamin J.,Geier III, G. Richard,Lindsey, Jonathan S.
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p. 1084 - 1092
(2007/10/03)
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