The direct synthesis of cyclic carbonate from carbon dioxide (CO₂) and olefins is attracting much interest in recent years. Herein, 1,5,7-triazabicyclo[4.4.0]dec-5-ene-functionalized phosphonate salts have been synthesized and characterized fully by Nuclear Magnetic Resonance (NMR), Electrospray Ionization Mass Spectrometry (ESI-MS) and Fourier Transform-infrared Spectroscopy (FT-IR) etc. The as-obtained salts have been employed as efficient catalysts for one-pot synthesis of cyclic carbonate from styrene and CO₂ through oxidative carboxylation reaction under very mild conditions (0.1 MPa CO₂, 80 °C) without any other solvents. The yield of cyclic carbonate can reach up to ca. 70 % in the presence of ZnBr₂ under the mild reaction condition. Besides, the catalyst can be recycled at least five times without significantly losing its catalytic activity. This approach can be extended to various styrene derivatives and good yields of cyclic carbonates was achieved under ambient conditions. Based on activity evaluation, reaction kinetics and DFT calculation, the six-membered carboxyphosphate species was proposed as a crucial intermediate species and played a crucial role in CO₂ activation. Finally, the reaction mechanism is proposed accordingly.

近年来，由二氧化碳（CO ₂）和烯烃直接合成环状碳酸酯备受关注。本文合成了1,5,7-三氮杂双环[4.4.0] dec-5-ene-官能化的膦酸盐，并通过核磁共振（NMR），电喷雾电离质谱（ESI-MS）和傅里叶变换-红外光谱（FT-IR）等。作为得到的盐已被用作有效的催化剂为一锅合成由苯乙烯和CO环状碳酸酯的₂非常温和的条件下通过氧化羧化反应（0.1兆帕CO ₂，80℃下），无需任何其他溶剂。环状碳酸酯的收率可以达到约。ZnBr ₂存在下70％在温和的反应条件下。此外，该催化剂可以循环至少五次而不会明显丧失其催化活性。该方法可以扩展到各种苯乙烯衍生物，并且在环境条件下获得了良好的环状碳酸酯收率。基于活性评估，反应动力学和DFT计算，六元羧基磷酸酯类被认为是关键的中间物种，并在CO ₂活化中起关键作用。最后，据此提出了反应机理。