Tandem one-pot synthesis of flavans by recyclable silica-HClO 4 catalyzed Knoevenagel condensation and [4 + 2]-Diels-Alder cycloaddition

Sandip B. Bharate, Ramesh Mudududdla, Jaideep B. Bharate, Narsaiah Battini, Satyanarayana Battula, Rammohan R. Yadav, Baldev Singh, Ram A. Vishwakarma

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An efficient one-pot multi-component synthesis of flavans using perchloric acid supported on silica as a recyclable heterogeneous catalyst has been described. This is the first report of direct one-step construction of a flavan skeleton from a phenolic precursor. The method involves a Knoevenagel-type condensation leading to in situ formation of transient O-quinone methide which further undergoes [4 + 2]-Diels-Alder cycloaddition with styrene to yield a flavan skeleton. The method provides easy access to a wide range of bio-active natural products viz. flavonoids, anthocyanins and catechins.

Original languageEnglish
Pages (from-to)5143-5150
Number of pages8
JournalOrganic and Biomolecular Chemistry
Issue number26
Publication statusPublished - 14 Jul 2012
Externally publishedYes

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