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  _____      ___     ______    __   __    ______  
 / ____||   / _ \\  |      \\  \ \\/ //  /_   _// 
/ //---`'  | / \ || |  --  //   \ ` //     | ||   
\ \\___    | \_/ || |  --  \\    | ||     _| ||   
 \_____||   \___//  |______//    |_||    /__//    
  `----`    `---`   `------`     `-`'    `--`

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Text this: Brønsted acid-catalyzed cycloisomerization of but-2-yne-1,4-diols with or without 1,3-dicarbonyl compounds to tri- and tetrasubstituted furans