Interaction of Palladium(II) Complexes with Amino-Alcohols: Synthesis of New Amino-Carbonyl Complexes, Key Intermediates to Cyclic Carbamates

Sustainable Route Toward N-Boc Amines: AuCl3 /CuI-Catalyzed N-tert-butyloxycarbonylation of Amines at Room Temperature

N-tert-butoxycarbonyl (N-Boc) amines are useful intermediates in synthetic/medicinal chemistry. Traditionally, they are prepared via an indirect phosgene route with poor atom economy. Herein, a step- and atom-economic synthesis of N-Boc amines from amines, t-butanol, and CO was reported at room temperature. Notably, this N-tert-butyloxycarbonylation procedure utilized ready-made substrates, commercially available AuCl₃ /CuI as catalysts, and O₂ from air as the sole oxidant. This catalytic system provided unique selectivity for N-Boc amines in good yields. More significantly, gram-scale preparation of medicinally important N-Boc amine intermediates was successfully implement, which demonstrated a potential application prospect in industrial syntheses. Furthermore, this approach also showed good compatibility with tertiary and other useful alcohols. Investigations of the mechanisms revealed that gold catalyzed the reaction and copper acted as electron transfer mediator in the catalytic cycle.

Methyl N-phenyl carbamate synthesis from aniline and methyl formate: carbon recycling to chemical products

Methyl N-phenyl carbamate was synthesized from aniline by using methyl formate as a green and efficient carbonylating agent. High yields were obtained at milder reaction conditions compared to the conventional CO/CH3 OH route. Studies on the reaction sequence led to suggest an alternative and more efficient route to the carbamate via formanilide as intermediate.

Away from phosgene: reductive carbonylation of nitroarenes and oxidative carbonylation of amines, understanding the mechanism to improve performance

Recent progress, with some emphasis on the author's own work, on the understanding of the mechanism of the reductive carbonylation of nitroarenes and of the oxidative carbonylation of amines is discussed, highlighting the close connection between the two reactions and trying to unify scattered data in the literature. Isocyanates, carbamates and ureas can be obtained by either procedure, without the need for the use of the toxic and corrosive phosgene.