Reimer-Tiemann reaction introduces an aldehyde group on to the aromatic ring of phenol, ortho to the hydroxyl group. This reacrtion involves electrophilic aromatic subsititution. It is a general method for the synthesis of subsituted salicyladehydes as depiced below:
The electrophile in this reaction is:
A. `:CHCl`
B. `.^(+)CHCl_(2)`
C. `:C Cl_(2)`
D. `.^(+)C Cl_(3)`