Synthesis of Naphthalene Derivatives via a Novel Gallium Trichloride
Catalyzed Cross-Coupling of Epoxides with Alkynes

Abstract

Gallium trichloride catalyzes the tandem ring opening of epoxides and cyclization with alkynes to generate naphthalene derivatives with complete regio control.

Key words

gallium trichloride - naphthalene - alkyne - epoxide

References

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9

Typical experimental procedure: Gallium trichloride (14.0 mg, 0.079 mmol, 10.6 mol%) was added to a solution of 1-phenyl-1-propyne (2b, 86.9 mg, 0.748 mmol) and trans-stilbene oxide (1b, 165.8 mg, 0.844 mmol) in CH₂Cl₂ (4.0 mL). The solution turned dark brown instantly. The reaction mixture was refluxed for 15 h then concentrated in vacuo. Subsequently, the crude mixture was purified by column chromatography on silica gel with hexane as eluent to give 1-phenyl-2-methylnaphthalene (3g, 147.3 mg, 0.50 mmol, yield 67%).