Consider the following transformation:
i. Tf$_2$O (1.1 equiv)
2-fluoropyridine (1.1 equiv)
CH$_2$Cl$_2$, -78 to 0 $^\circ$C
ii. EtMgBr (2 equiv), -78 $^\circ$C
then HCl (xs)
Is this a regioselective, chemoselective, diastereoselective or enantioselective reaction? Justify.
More than one type of selectivity can be involved. (15 pts)