Rhodium-catalyzed ortho-deuteration of anilines.

A practical and highly regioselective rhodium-catalyzed protocol for the site-selective ortho-deuteration of anilines via a traceless aminophosphine directing group is reported. The method relies on readily available [Rh(COD)Cl]2 as catalyst and heavy water as an inexpensive and operationally simple deuterium source, and proceeds under mild conditions. Complete regioselectivity for the ortho and ortho' positions is consistently achieved, with high levels of deuterium incorporation as well as broad functional group tolerance. The deuteration moreover extends beyond simple anilines to more complex scaffolds, including tetrahydroisoquinolines, carbazoles, diarylamines or naphthylamines.