Ferrocenyl thioketones react with donor-acceptor cyclopropanes in dichloromethane at room temperature in the presence of catalytic amounts of Sc(OTf)3 yielding tetrahydrothiophene derivatives, products of formal (3+2)-cycloaddition reactions, in moderate to high yields. In all studied cases, dimethyl 2-arylcyclopropane dicarboxylates react with corresponding aryl ferrocenyl thioketones in a completely diastereoselective manner to form single products in which (C-2)-Ar and (C-5)-ferrocenyl groups are oriented in a cis-fashion. In contrast, the same cyclopropanes undergo reaction with alkyl ferrocenyl thioketones to form nearly equal amounts of both diastereoisomeric tetrahydrothiophenes. Low selectivity was also observed in the reaction of 2-phthalimide-derived cyclopropane with ferrocenyl phenyl thioketone.
Keywords: (3+2)-cycloaddition reactions; donor-acceptor cyclopropanes; ferrocenyl thioketones; sulfur heterocycles; tetrahydrothiophenes
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Mloston, G.; Kowalczyk, M.; Augustin, A. U.; Jones, P. G.; Werz, D. B. Beilstein Arch. 2020, 202043. doi:10.3762/bxiv.2020.43.v1
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