Palladium-Catalyzed Carbonylation of Azides and Mechanistic Studies
Jiyao Feng
a
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Plant Protection, and College of Science, China Agricultural University, Beijing 100193, P. R. of China
,
Zhen Zhang
b
College of Chemistry & Chemical Engineering, Yantai University, Yantai, 264005, P. R. of China eMail: 91030@cau.edu.cn eMail: zhangzhh@cau.edu.cn
,
Xuefeng Li∗
a
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Plant Protection, and College of Science, China Agricultural University, Beijing 100193, P. R. of China
,
Zhenhua Zhang∗
a
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Plant Protection, and College of Science, China Agricultural University, Beijing 100193, P. R. of China
› InstitutsangabenThis project is supported by the National Natural Science Foundation of China (Grant No. 21672256).
Isocyanates are widely applied in the fields of materials science, drug discovery and chemical industry processes. Palladium-catalyzed carbonylation of azides with carbon monoxide (CO) is reported as a powerful method for simple and efficient access to isocyanates, which are important precursors for preparing structurally meaningful urea, carbamate and amidine derivatives. In this account, we provide an overview on the synthesis of isocyanates and their subsequent reactions to obtain diverse nucleophilic addition products. In addition, with particular emphasis on our mechanistic studies of the Pd-catalyzed carbonylation process, we outline the identification of the actual catalytic species, the possible intermediates and some key factors in the catalytic cycle.
1 Introduction
2 Palladium-Catalyzed Reaction of Azides with CO and Subsequent Nucleophilic Additions
3 Mechanistic Studies on the Palladium-Catalyzed Reaction of Azides with CO
3.1 Studies on the Actual Catalytic Species and the Key Intermediates in the Activation and Carbonylation of Acyl Azides
3.2 Study of the Sulfonylurea Product Self-Catalyzed Carbonylation of Sulfonyl Azides
3.3 Study of the Actual Catalytic Pattern of the Pd/C Catalyst
30 All calculations were performed using the Gaussian 09 program. The density functional theory (DFT) formalism with the B3LYP functional and LanL2DZ mixed basis sets for Pd atoms and the 6-31G(d,p) basis sets for other main group atoms were applied. Thermodynamic parameters including the Gibbs free energies at 298 K were obtained by frequency calculations. Transition states are realized by the presence of a single negative frequency. The electronic energies of the optimized structures were further corrected by single-point calculations of the M06-D3 functionals with SDD for Pd atoms and 6-311+G(d,p) for other atoms. Single-point solvation energy corrections in THF computed by the ief-PCM method were added to the gas-phase free energy.
31
Heidenreich RG,
Krauter JG. E,
Pietsch J,
Köhler K.
J. Mol. Catal. A: Chem. 2002; 182–183: 499
