Synthesis of a [2]benzazepine analogue of clavizepine

The synthesis of N-tosylbenzopyran[2]benzazepinone 2 using a simple protocol for assembly of an azepine ring on the xanthene skeleton is described. Formation of the CC bond between C9 of the xanthen-9-ol 7 and the β-C of N-tosyl aminoacetaldehyde dimethyl acetal leads to 10, which upon treatment with formaldehyde undergoes ring closure.