- Development of Gold-catalyzed [4+1] and [2+2+1]/[4+2] Annulations between Propiolate Derivatives and Isoxazoles
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Two new gold-catalyzed annulations of isoxazoles with propiolates have been developed. Most isoxazoles follow an initial O attack on the alkyne to afford a [4+1] annulation product. This process results in a remarkable alkyne cleavage of initial propiolates. Unsubstituted isoxazoles proceed through an N attack step to yield formal [2+2+1]/[4+2] annulation products. These two annulation products arise initially from two seven-membered heterocyclic intermediates, which then lead to products.
- Sahani, Rajkumar Lalji,Liu, Rai-Shung
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supporting information
p. 1026 - 1030
(2017/01/18)
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- THALLIUM AND MERCURY IN PYRROLE CHEMISTRY. USE OF C-THALLIATED AND C-MERCURIATED PYRROLE DERIVATIVES FOR SELECTIVE RING FUNCTIONALISATIONS via ipso-DETHALLIATION AND -DEMERCURIATION REACTIONS
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The use of C-thalliated and C-mercuriated pyrroles to achieve selective introduction of various functional groups in a β position is described.High yields of hardly accessible pyrrole derivatives (such as nitropyrrole) can thus be obtained.
- Monti, Donato,Sleiter, Giancarlo
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p. 771 - 774
(2007/10/02)
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- Deacylation of Pyrrole and other Aromatic Ketones
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Ethyl 4-acetyl-3,5-dimethyl-1H-pyrrole-2-carboxylate (1a) reacts rapidly with ethylene glycol in refluxing benzene with p-toluenesulfonic acid or perchloric acid as a catalyst to give ethyl 3,5-dimethyl-1H-pyrrole-2-carboxylate (3) in high yield (96 percent).Various 2- and 3-acylpyrroles can be efficiently deacylated by using this procedure.Other ketones which undergo deacylation include phenyl(2-phenylindol-3-yl)methanone (19), 1-(5-methyl-1-phenylpyrazol-4-yl)ethanone (20), and 2,4-dimethoxybenzophenone.Certain pyrrole ketones where the acyl group is flanked by two ring methyl groups are also cleaved under acidic conditions by using ethanedithiol.
- Moon, M. W.,Wade, R. A.
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p. 2663 - 2669
(2007/10/02)
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