Transfer hydroamination of O-formylated hydroxylamines derivatives

International audienceC–N bond are present in many molecules from the pharmaceutical industry and the formation of this bond represents 35 % of all the reactions performed in this field.[1] Usually, they are formed by N-alkylation, cross-couplings, or reductive amination. Another type of reaction is presenting an important interest, the hydroamination[2] although overlooked. Indeed, despite being a powerful method to form C–N bonds, hydroamination is also limited by thermodynamic and kinetic effects such as a low difference of energy between reactants and products, or electrostatic repulsions. This reaction implies an amine[3], and particularly an N–H bond which will be added across an unsaturated compound such as an alkene to form a C–N bond and a C–H bond with a perfect atom economy. Over the past years, O-acylated hydroxylamines[4] or azanyl esters[5] have also been used with alkenes and hydride donors to perform similar reactions.We turned our interest toward developing a catalytic method to perform the hydroamination using Oformylated azanyl esters, without using hydride donor since the formate plays the role of a hydride donor. This reaction is, thus, a transfer hydroamination. Here, we use a linker, CO2, to make the nitrogen more electrophilic and the hydrogen more nucleophilic. The N–O bond is also weaker than a C-N bond,therefore, a catalyst can easily be inserted in that bond and the loss of CO2 allows to drive the equilibrium. This methodology allows us to perform hydroamination with CO2 as the only stoichiometric waste and to avoid the electrostatic repulsions between the lone pair of the nitrogen and π-orbitals of the alkene