Ozonolysis of unsaturated organotrifluoroborates.

Organotrifluoroborates are robust reagents capable of withstanding ozonolysis of remote alkenes, thus providing a new route to oxo-substituted organotrifluoroborates. The primary ozonides initially generated upon ozonolysis can be reduced with Zn/AcOH to afford the carbonyl compounds. Alternatively, capture of the carbonyl oxides with either an appropriate N-oxide or H2O easily gives the desired oxo-substituted organotrifluoroborates. Both unsaturated alkyltrifluoroborates and aryltrifluoroborates effectively participate in the reaction. The process provides oxo-functionalized organotrifluoroborates that cannot be prepared directly via either transmetalation or hydroboration protocols.