Description:
<jats:p> The mechanism of the Schmidt rearrangement has been examined in the conversion of chromanones to 1,4- and 1,5-benzoxazepinones. With substituents in the 6-, 7-, or 8-position, only electronic effects prevail resulting in the exclusive formation of 1,4-benzoxazepinones. Steric effects come into play with increasing bulk of substituents in the 5-position of the chromanone. Results now presented favor more than one pathway for the products to arise. Nuclear magnetic resonance spectra have been used to distinguish between the isomeric 1,4- and 1,5-benzoxazepinones.Several new chromanones have been synthesized. </jats:p>