Abstract RFC CMgX reacts with Ac 2 O to give not only MeC (O) C CR F but also MeC (O) CX C (RF) C (O) Me, and with CF 3 COOPr it gives CF 3 C (O) CH C (OPr) RF not CF 3 C (O) C CR F; RFC CMgBr reacts with Cl 2 to give RFC CBr rather than RFC CCl, while with Br 2 RFC CMgI similarly gives RFC CI rather than RFC CBr.
