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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