Tandem Reaction of Arynes with Tertiary Amines and Aldehydes: Formation of 9-and 10-Membered Dibenzo[1,5]oxaza Heterocycles

The aryne-mediated three-component reaction of arynes, tertiary amines, and aldehydes followed by intramolecular nucleophilic aromatic substitution afforded novel 9- and 10-membered heterocycles. Thus, the reaction of 2-(trimethylsilyl)phenyl triflate with N-phenylmorpholine and benzaldehyde in the presence of CsF gave o-morpholinobenzhydryl phenyl ether in 76% yield. By using N-methylindoline, nine-membered dibenzo[1,5]oxazonines were synthesized in moderate yields.