Valorization of CO₂: Preparation of 2-Oxazolidinones by Metal–Ligand Cooperative Catalysis with SCS Indenediide Pd Complexes

Abstract

The capture and utilization of CO 2 to prepare highvalue compounds is very attractive chemically and highly desirable socially. Indenediide-based Pd SCS pincer complexes are shown here to promote the carboxylative cyclization of propargylamines leading to 2-oxazolidinones under mild conditions (0.5−1 bar of CO 2 , DMSO, 40−80 °C, 1−5 mol % Pd loading). The indenediide Pd complex is competitive with known catalysts. It proved successful for a wide range of propargylamines, including hitherto challenging substrates such as secondary propargylamines bearing tertiary alkyl groups at nitrogen, primary propargylamines, and propargylanilines. Thorough experimental (NMR) and computational (DFT) investigations were undertaken to gain mechanistic insights. Accordingly, (i) the resting state of the catalytic cycle is a Pd DMSO complex; (ii) the indenediide backbone and Pd center act in concert to activate the carbamic acid intermediate and promote its cyclization; (iii) proton shuttling is essential to lower the activation barriers of the initial amine carboxylation as well as of the proton transfers between the ligand backbone and the organic fragments at Pd.

Synthesis of Oxazolidin‐2‐ones from Unsaturated Amines with CO2 by Using Homogeneous Catalysis

“…In 2017, Martin‐Vaca, Bourissou, and co‐workers developed a new cooperatively catalyzed CO 2 ‐fixation reaction of propargylic amines to afford a range of oxazolidin‐2‐ones . An indenediide‐based palladium pincer complex served as a highly active catalyst that enabled some challenging substrates, such as primary propargylic amines and secondary propargylic amines that contained tertiary alkyl groups on the nitrogen atom, to afford the corresponding oxazolidin‐2‐ones (Scheme ).…”

Phosphine Ligand‐Free Ruthenium Complexes as Efficient Catalysts for the Synthesis of Quinolines and Pyridines by Acceptorless Dehydrogenative Coupling Reactions

“…Among various homogeneous transition metal catalysts, Ru-complexes are the most efficient reported to date. [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][60][61][62][63] Metal-ligand cooperative catalysis [64][65][66][67] can dramatically improve catalytic performance of ADC reactions using pincer ligands bearing NH, OH or CH 2 functionality. [40][41][42][43][44][68][69][70][71][72][73][74][75][76][77][78][79][80][81] Milstein, [40] Sun, [41] Yu, [42] Kundu [43] and Chen [44] have independently developed bifunctional Ru(II) catalysts for the synthesis of pyridine and quinoline derivatives (Scheme 1), b...…”

Pd NPs Decorated on POPs as Recyclable Catalysts for the Synthesis of 2‐Oxazolidinones from Propargylic Amines via Atmospheric Cyclizative CO2 Incorporation

“…In recent times, Bourissou and co‐researchers have describe in their own work that indenediide‐based Palladium SCS pincer materials was advantageous than other well‐reported catalytic system to catalyze the carboxylative reaction of several propargylamine derivatives (Scheme , eq. 2) …”