Brønsted acid-catalyzed one-pot tandem annulation/[5+2]-cycloaddition of o-propargyl alcohol benzaldehydes with alkynes: regioselective and stereoselective synthesis of dibenzo[a,f]azulen-12-ones

The one-pot synthesis of dibenzo[a,f]azulen-12-ones has been established starting from o-propargyl alcohol benzaldehydes and alkynes. The key azulenone bicyclic skeletons were formed through intramolecular Meyer-Schuster rearrangement and intermolecular [5+2]-cycloaddition sequence. This annulation process showed high atom and step economy, regioselectivity and stereoselectivity by creating three C-C and one C-O bonds.