The reaction of o-amino aryl carboxylic acids with Grignard reagents. The unusual effect of the N-protecting group on aryl ketone formation

The addition of Grignard reagents to the o-amino aryl carboxylic acids without any additive forms the tertiary carbinol as a major product. Unexpectedly, the aryl ketones are formed as the only isolated product if o-amino moiety of anthranilic acids is protected with Boc, trifluoroacetyl, and pivaloyl protecting groups.