Reactivity of rhodium hydrido and silyl complexes towards 1,1-difluoroallene

Versatile Reaction Pathways of 1,1,3,3,3‐Pentafluoropropene at Rh(I) Complexes [Rh(E)(PEt3)3] (E=H, GePh3, Si(OEt)3, F, Cl): C‐F versus C‐H Bond Activation Steps

“…The lowest energy isomers exhibit an anti ‐conformation for the CF 3 moiety and the silyl/germyl ligand (Figure 1) and a C−C bond distance of 1.463 Å for both complexes was found, which is in good agreement with the rhodacyclopropane model. Note that comparable silyl complexes with other coordinated olefins such as hexafluoropropene have been described in a similar manner [7e,10] …”

“…Note that comparable silyl complexes with other coordinated olefins such as hexafluoropropene have been described in a similar manner. [ 7e , 10 ]…”

“…These reaction pattern are in contrast to C−F bond activation reactions of heteroaromatics at [Rh(E)(PEt 3 ) 3 ] (E=GePh 3 , B(O 2 C 2 Me 4 ) or Si(OEt) 3 ), for which ligand‐supported C−F bond cleavage steps were proposed [7a,c,26] . Nevertheless, the described reaction pathways for 1,1,3,3,3‐pentafluoropropene can also be set into a broader context and compared with characteristic C−H bond and C−F bond reaction pathways of the rhodium(I) complexes [Rh(E)(PEt 3 ) 3 ] towards olefins [5o,7c,e,f,10] . Some similarities are found for tetrafluoropropenes, but the distinctive behavior of the germane versus the silane is pronounced.…”

Rhodium(I) Complexes as Useful Tools for the Activation of Fluoroolefins

“…phosphine scavenger and this might hamper any C-F bond activation. 20 Although it is common to propose a precoordination of the fluoroolefin to the transition metal as the initial step for its activation, the isolation of such products has not often been described. However, coordination of hexafluoropropene has also been reported at palladium(0) or nickel(0) centers, followed in both cases by C-F bond activation in the presence of Lewis acids to yield, respectively, cationic allyl complexes by C(sp 3 )-F bond activation, 21 or a perfluoropropenyl complex by activation of the fluorine atom at the geminal position with respect to the CF 3 substituent, 22 which resembles the regioselectivity observed at [Rh{C(CF 3 )=CF 2 }(PEt 3 ) 3 ] (17).…”

“…48 The allene rhodium complex [Rh(η 2 -CH 2 =C=CF 2 )(η 3 -CH 2 CHCF 2 )(PEt 3 ) 2 ] (36), which is furnished by treatment of 1 with two molecules of difluoroallene, has also been described. 20 Attempts to obtain a functionalized olefin derivative from 3,3,3-trifluoropropene through catalytic processes at rhodium were unsuccessful. Nonetheless, hydrosilylation, hydroboration or hydrogermylation reactions were achieved using HSiPh 3 , HBpin or HGeR 3 (R = Ph, Et, nBu), respectively, as hydrogen sources (Scheme 15).…”