Insertion of CO2 and CS2 into Bi-N bonds enables catalyzed CH-activation and light-induced bismuthinidene transfer

The uptake and release of small molecules continue to be challenging tasks of utmost importance in synthetic chemistry. The combination of such small molecule activation with subsequent transformations to generate unusual reactivity patterns opens up new prospects for this field of research. Here, we report the reaction of CO2 and CS2 with cationic bismuth(iii) amides. CO2-uptake gives isolable, but metastable compounds, which upon release of CO2 undergo CH activation. These transformations could be transferred to the catalytic regime, which formally corresponds to a CO2-catalyzed CH activation. The CS2-insertion products are thermally stable, but undergo a highly selective reductive elimination under photochemical conditions to give benzothiazolethiones. The low-valent inorganic product of this reaction, Bi(i)OTf, could be trapped, showcasing the first example of light-induced bismuthinidene transfer.

Automated summary

The uptake and release of small molecules pose significant challenges in synthetic chemistry. By combining small molecule activation with subsequent transformations, new reactivity patterns can be generated, opening up new possibilities for research in this field. In this study, the reaction between CO2 and CS2 with cationic bismuth(iii) amides was investigated. CO2 uptake resulted in isolable but metastable compounds, which underwent CH activation upon CO2 release. These transformations were successfully transferred to the catalytic regime, resembling CO2-catalyzed CH activation. The CS2 insertion products were thermally stable, but under photochemical conditions, they selectively underwent reductive elimination to form benzothiazolethiones. Furthermore, the low-valent inorganic product of this reaction, Bi(i)OTf, was trapped, demonstrating the first example of light-induced bismuthinidene transfer.