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Y(OTf)3-Catalyzed Formal (3 + 2) Cycloadditions of Donor-Acceptor Cyclopropanes with KSCN under Mechanochemical
Wandi Li1,2, Leonie Herzog1, Yijie Hu1
1Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany.
Abstract:
A mechanochemical (3 + 2) cycloaddition of donor-acceptor cyclopropanes (DACs) with potassium thiocyanate leading to dihydrothiophene derivatives has been developed. Using Y(OTf)3 as a catalyst, the reactions proceed without solvents or additives, tolerating various substrates to afford the products in moderate to good yields. Mechanistic studies suggest a sequence of ring opening and cyclization followed by a decarboxylation step enabled by cooperative Lewis acid/thiocyanate activation. Overall, the method provides an efficient strategy for sulfur-containing heterocycles.
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