A Convenient and Unambiguous Synthesis of 2 (or 7)-Chloronaphthalenes from Substituted α-Tetralones

Chemoselective Reduction of Trichloromethyl Compounds to gem-Dichloromethyl Groups Following Appel’s Reaction Protocol

“…Multiplicities are reported as singlet (s), doublet (d), triplet (t), quartet (q), multiplet (m), and broad singlet (bs). 13 C NMR signals are reported using 77.0 ppm (CDCl 3 ) as the internal reference.…”

“…1 H NMR (300 MHz, CDCl 3 ): δ 10.05 (brs, 1H), 7.24−7.22 (m, 1H), 7.20−7.17 (m, 1H), 6.52 (s, 1H), 6.38 (td, J = 4.2, 2.5 Hz, 1H). 13…”

“…1 H NMR (300 MHz, CDCl 3 ): δ 8.28 (dd, 1H, J = 8.4, 1.2 Hz), 7.85 (dt, 1H, J = 7.5, 1.2 Hz), 7.75 (td, 1H, J = 8.4, 1.5 Hz), 7.62 (dd, 1H, J = 7.5, 1.5 Hz), 6.38 (s, 1H). 13 Dichloroacetylmorpholine (2h). 23 This compound was purified by flash column chromatography using hexanes−EtOAc (95:5) and obtained as a white solid (135 mg, 68% yield); crystallization (hexanes−CH 2 Cl 2 ); mp 64−65 °C.…”

“…1 H NMR (300 MHz, CDCl 3 ): δ 6.21 (s, 1H), 3.76−3.72 (m, 6H), 3.67−3.64 (m, 2H). 13 2-N,N-Dimethylamino-4-(dichloromethyl)-1,3,5-triazine (2i). This compound was purified by flash column chromatography using hexanes−EtOAc (95:5) and obtained as a pale yellow oil (195 mg, 94% yield).…”

“…7 Likewise, they are widely used as synthetic precursors to afford the corresponding aldehydes under basic conditions 8 as well as precursors for gem-difluoromethyl groups by the double nucleophilic substitution of the chlorides by fluoride ions. 9 General methods to prepare dichloromethyl compounds involve Lewis acid catalyzed acylation of arenes, 10 oxyhalogenation of alkynes, 11 and chlorination of ketones which implicates using different types of chlorine sources, 12 such as sulfuryl chloride, 13 thionyl chloride, 14 N-chlorosuccinimide, 15 and 1,3-dichloro-5,5-dimethylhydantoin (DCDMH). 16 However, few methods have been described to allow the formation of gem-dichloromethyl compounds employing trichloromethyl derivatives as starting materials.…”