Revisiting a Classic Transformation: A Lossen Rearrangement Initiated by Nitriles and "Pseudo-Catalytic" in Isocyanate.

The direct conversion of a hydroxamic acid to an amine has been accomplished in a single step in the synthesis of HIV drug candidate BMS-955176. This process utilizes catalytic base and proceeds under mild conditions (CHCN, cat. DBU, 60 °C), without the need for strong electrophiles required for typical Lossen rearrangements, and can be applied to aliphatic and aromatic hydroxamic acids.