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Access to Multisubstituted Furan-3-carbothioates via Cascade Annulation of α-Oxo Ketene Dithioacetals with Isoindoline-1,3-dione-Derived Propargyl Alcohols. | LitMetric

A Brønsted acid-promoted, unprecedented formal (3 + 2) annulation strategy for the synthesis of multisubstituted furan-3-carbothioates is reported. This transformation represents the first regioselective annulation of α-oxo ketene dithio-acetals as 1,3-bis-nucleophiles in a cascade manner. The choice of isoindoline-1,3-dione-derived propargyl alcohols is crucial to the uncommon annulation mode between an alkyne-type bis-electrophile and a 1,3-bis-nucleophile under metal-free conditions. The scale-up of the synthesis and several interesting transformations of an as-synthesized product were further investigated. A Nazarov-like cyclization is proposed for the ring-closure process according to the experimental observations.

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http://dx.doi.org/10.1021/acs.joc.8b00401DOI Listing

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