- Photochemical synthesis of pyrrole derivatives by desulfurization of 2,5-dihydro-1H-pyrrole-2-thiones and [2 + 2] cycloaddition of 2,5-dihydro-1H-pyrrole-2-thiones with alkenes
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The photochemical reactions of the 2,5-dihydro-1H-pyrrole-2-thiones 2 have been examined. Irradiation of 2,5-dihydro-1H-pyrrole-2-thiones 2 in the presence of triethylamine gives desulfurization products, the pyrroles 3, or reduction products, the pyrrolidine-2-thiones 4, depending on the substituent on the nitrogen atom of thione 2. This reaction can be explained by a sequential electron/proton-transfer mechanism from the amine to the excited pyrrolethione. Irradiation of thiones 2 in the presence of alkenes 5 gives 2-alkylated pyrroles 6-14. The formation of these photoproducts can be explained in terms of the intermediacy of spiroaminothietanes, which are derived by [2 + 2] photocycloaddition of the C=S bond of thione 2 and the C=C bond of alkene 5.
- Nishio, Takehiko
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p. 885 - 889
(2007/10/03)
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- Novel Route to 4,5,6,7-Tetrahydroindoles and Pyrroles
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Treatment of cyclic unsaturated amides, 1,4,5,6,7,7a-hexahydro-2H-indol-2-ones 1, with Lawesson's reagent yielded unexpected products, 4,5,6,7-tetrahydroindoles 2, in moderate yield.Re
- Nishio, Takehiko,Okuda, Norikazu,Kashima, Choji
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p. 899 - 902
(2007/10/02)
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