Rhodium( i )-catalyzed Pauson–Khand-type reaction using formic acid as a CO surrogate: an alternative approach for indirect CO 2 utilization

• Published in: Green chemistry : an international journal and green chemistry resource : GC Vol. 21; no. 3; pp. 509 - 514
• Main Authors: Lang, Xian-Dong, You, Fei, He, Xing, Yu, Yi-Chen, He, Liang-Nian
• Format: Journal Article
• Language: English
• Published: 04.02.2019
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/C8GC03933J

Formic acid is found to be an ideal CO surrogate for the rhodium( i )-catalyzed Pauson–Khand-type (PK-type) reaction of various substituted 1,6-enynes to afford bicyclic cyclopentenones in moderate to good yields. High TON value of up to 263 and good results in the gram-scale experiment were also obtained, demonstrating the efficacy of this methodology. In addition, heterocyclic molecules of pharmaceutical importance were also furnished via inter- or intra-molecular hetero-PK-type reactions, further broadening the application of current strategy. In this protocol, formic acid was utilized as a bridging molecule for the conversion of CO 2 to CO, since formic acid is manufactured via catalytic hydrogenation of CO 2 and releases CO in the presence of acetic anhydride readily. Therefore, this methodology represents a green and indirect approach for chemical valorization of CO 2 in the preparation of value-added compounds.