Rhodium complex fluoroalkene

The differences in the steric effect between catecholborane and pinacolborane, and the valence effect between a cationic or neutral rhodium complex reverse the re-gioselechvity for fluoroalkenes (Scheme 1-4) [26]. The reaction affords one of two possible isomers with excellent regioselectivity by selecting borane and the catalyst appropriately, whereas the uncatalyzed reaction of 9-BBN or SiaiBH failed to yield the hydroboration products because of the low nucleophilicity of fluoroalkenes. The regiochemical preference is consistent with the selectivity that is observed in the hydroboration of styrene. Thus, the internal products are selectively obtained when using a cationic rhodium and small catecholborane while bulky pinacolborane yields terminal products in the presence of a neutral rhodium catalyst. 

Diazoalkanes were readily decomposed and underwent [2+l]-type cycloaddition to alkenes in the presence of catalytic amounts of rhodium complexes. Rh2(OAc)4 is the simplest complex for the reaction. For example, fluoro-cyclopropane 134 was prepared by the carbene addition to fluoroalkene 133 (Scheme 1.64) [108]. A copper catalyst also catalyzed the addition reaction. 

Garbon-fluorine bonds of fluoroalkenes can be cleaved by reaction with metal hydrides to give HF and vinyl complexes. Thus, the rhodium compound [Rh (Z)-GF=GF(GF3) (PEt3)3] can be synthesized by regioselective G-F bond activation of hexafluoropropene at [RhH(PEt3)3] in the presence of Et3N/Gs2G03 (Scheme 10 left). ... 

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