A facile route to the benzooxabicyclo[3.2.1]octane (2,3,4,5-tetrahydro-2,5-methano-1-benzoxepine) system: application to a short synthesis of filiformin
Abstract
Photolytic ethylene addition to 3-methoxychromones 3a–cfurnished the 3-hydroxyoxetanes4a–c; reduction to the diols 5a–c followed by acid-catalysed rearrangement afforded the benzooxabicyclo[3.2.1]octanones 6a–cand bromination of 6c furnished7, which has previously been converted to filiformin 2.