B(C 6 F 5 ) 3 -Catalyzed transfer 1,4-hydrostannylation of α,β-unsaturated carbonyls using iPr-tricarbastannatrane.

Tris(pentafluorophenyl)borane, B(C6 F5 )3 , has been found to be an effective catalyst to access the hydridoborate anion, [N(CH2 CH2 CH2 )3 Sn][HB(C6 F5 )3 ], via hydride abstraction from the hypercoordinated tin reagent, iPr-tricarbastannatrane. This process has been applied to the B(C6 F5 )3 -catalyzed transfer 1,4-hydrostannylation of electron-deficient olefins, namely benzylidene barbituric acids. Insights into the mechanism have been obtained via a series of1 H,2 H,11 B,13 C, and119 Sn NMR spectroscopy, mass spectrometry, and labeling experiments.