Multigram Synthesis of Heterabicyclo[n.1.0]alkan‐1‐yl Trifluoroborates

An approach to the synthesis of oxa‐ and azabicyclo[ n .1.0]alkan‐1‐yl trifluoroborates on a multigram scale was developed. Two synthetic strategies were evaluated: the first based on the lithiation–borylation of the corresponding 2‐bromoallyl derivatives, and the other relying on regioselective hydroboration of the appropriate hetera‐substituted enynes. The second method appeared to be more efficient in terms of scalability and substrate scope. Further steps included ring closing‐metathesis, mild palladium‐catalyzed cyclopropanation with diazomethane, and reaction with KHF 2 and furnished the title compounds in up to 50 g scale in a single run (10–41 % overall yield, 4–5 steps).