Pincer‐Supported Perfluororhodacyclopentanes: High Nucleophilicity of the M−CF Bond.

Perfluororhodacyclopentane supported by PBP pincer ligand PBP‐RhIII(CF2)4 (2) was prepared from PBP‐RhI‐PPh3 (1) and tetrafluoroethylene (TFE). By scXRD analysis, it was revealed that the Rh−CF bond trans to the boryl ligand was largely elongated compared to the one in the apical position. Although M−CF bonds of perfluorometallacyclopentanes are known to be very stable, 2 shows high reactivity toward hydrogenolysis, iodinolysis and protonolysis, thanks to the strong trans‐effect of the highly σ‐donating boryl ligand. Analogous PCP pincer complex PCP−RhIII(CF2)4 (4) showed slower reaction rate both in oxidative cyclization with TFE and hydrogenolysis of Rh−CF bond. Catalytic production of 1,1,2,2,3,3,4,4‐octafluorobutane from two TFE and hydrogen in one pot was achieved via repetitive oxidative cyclization of TFE and Rh followed by the hydrogenolysis of Rh−CF bonds. This report demonstrates the possible application of PBP‐pincer skeleton to the preparation of fluorinated compounds from TFE. [ABSTRACT FROM AUTHOR]