Selective cyclization of alkynols and alkynylamines catalyzed by potassium tert-butoxide

Potassium tert-butoxide (t-BuOK) was found to be an effective catalyst for the cyclization of aromatic alkynols and alkynylamines. In the presence of 10 mol % t-BuOK, a range of alkynols were converted to the corresponding exo-cyclic enol ethers as pure Z-stereoisomers with 100% selectivity and moderate to excellent yields. Moreover, the cyclization of alkynylamines was also achieved to afford indoles and isoindolin-1-ones in good yields.

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