The Pd -catalyzed C(sp )-H arylation of 2-bromo-N-methylanilides leads to unstable benzazetidine intermediates that rearrange to benzoxazines through 4π electrocyclic ring-opening and 6π electrocyclization. The introduction of a bulky, non-activatable amide group on the nitrogen atom was key to favor the challenging reductive elimination step and disfavor undesired reaction pathways.

The Pd 0 -catalyzed C(sp 3 )-H arylation of 2-bromo-N-methylanilides leads to unstable benzazetidine intermediates that rearrange to benzoxazines through 4p electrocyclic ringopening and 6p electrocyclization. The introduction of abulky, non-activatable amide group on the nitrogen atom was key to favor the challenging reductive elimination step and disfavor undesired reaction pathways.