Methane, dichloromethoxy- → 7-Fluoronaphthalene-1-carbaldehyde

Reaction equation

[F:1][C:2]1[CH:11]=[CH:10][C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[CH:3]=1.[CH3:12][O:13]C(Cl)Cl>[Ti](Cl)(Cl)(Cl)Cl.C(Cl)Cl>[F:1][C:2]1[CH:3]=[C:4]2[C:9]([CH:8]=[CH:7][CH:6]=[C:5]2[CH:12]=[O:13])=[CH:10][CH:11]=1

Participants

Procedure

By the method of Preparation 1, 2-fluoronaphthalene (10 g., 0.068 mole) in 200 ml. of methylene chloride was reacted with titanium tetrachloride (25.5 g., 14.7 ml. 0.136 mole) and 1,1-dichloromethyl methyl ether (10.1 g., 0.088 mole). The resulting crude product (11 g.) was first recrystallized from hexane to yield 7-fluoro-1-naphthaldehyde [2.5 g., m.p. 95°-96° C., Rf 0.25 (1:1 chloroform:hexane)]. The mother liquor was evaporated to dryness and the residue chromatographed on 400 g. of silica gel, eluting initially with 3:1 hexane:chloroform and then with 3:2 hexane:chloroform. The column was monitored by tlc. Fractions contain clean 2-fluoro-1-naphthaldehyde [Rf 0.31 (3:2 hexane:chloroform)] were combined and evaporated to dryness, yielding purified 2-fluoro-1-naphthaldehyde (2.8 g., m.p. 60°-62° C.).