Kinetics of the BpCu-catalyzed carbene transfer reaction (Bp = dihydridobis(1-pyrazolyl)borate). Is a 14-electron species the real catalyst for the general copper-mediated olefin cyclopropanation?

1. Díaz-Requejo, M.M.
2. Belderrain, T.R.
3. Nicasio, M.C.
4. Prieto, F.
5. Pérez, P.J.