engleski

Catalytic Coupling of CO2 with Propargyl Alcohol Substrates

Carbon dioxide (CO2) is an abundant and sustainable C1 building block for producing valuable synthetic intermediates and biologically active chemicals, such as carbonates and carbamates.1 Based on density functional theory (DFT) calculations (using the B2PLYP/B3LYP), we have evaluated several propargyl alcohols as CO2 trapping substrates by comparing the thermodynamic stability between starting materials and final carbonates. Exergonic reactions are predicted for conjugated propargyl alcohols when additional C-C bonds are formed via domino reactions. We have therefore envisaged palladium-catalyzed intermolecular reactions on suitable propargylic alcohols bearing an aryl halide moiety to produce α-alkylidene cyclic carbonates.2 The fixation of CO2 can be accomplished by the alkoxide produced in the basic medium, and the cyclization can be mediated by the Pd catalyst which is expected to be inserted by oxidative addition to the aryl halide bond. Reductive elimination may afford the final product and regenerate the catalyst. We present herein our recent computational and experimental results according to the reaction scheme shown in Figure 1. 1 Q. Liu, L. Wu, R. Jackstell, M. Beller, Nat. Commun. 2015, 6, 5933 ; S. Wang, C. Xi, Chem. Soc. Rev. 2019, 48, 382-404. 2 K. Iritani, N. Yanagihara, K. Utimoto, J. Org. Chem. 1986, 51, 5499-5501 ; Y. Inoue, Y. Itoh, I.-F. Yen, S. Imaizumi, J. Mol. Cat. 1990, 60, L1-L3 ; S. Sun, B. Wang, N. Gu, J.-T. Yu, J. Cheng, Org. Lett. 2017, 19, 1088-1091.

carbon dioxide, palladium catalysis, cyclic carbonate

Funding: HRZZ IP-2019-04-8846 INDICATIOR; University of Rijeka (uniri-prirod-18-102-1237); European Fund for Regional Development (Research Infrastructure for Campus based Laboratories)