One-Step Conversion of Acetophenones to α -Haloacetophenone Dimethyl Acetals Using DCDMH/DBDMH and Molecular Sieve in Methanol

Using DCDMH/DBDMH as N-halo reagent, piperidine as catalyst, and 4-A molecular sieve as water-removing agent, α-haloacetophenone dimethyl acetals were directly obtained from the solvent of methanol. As to the substrates with electron-withdrawing groups, the conversions were 80–100%.