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.

gallium trichloride - naphthalene - alkyne - epoxide

References

1a Shore NE. Chem. Rev.  1988,  88:  1081 

1b Dötz KH. Angew. Chem., Int. Ed. Engl.  1984,  23:  587 

2a Yoshikawa E. Radhakrishnan KV. Yamamoto Y. J. Am. Chem. Soc.  2000,  122:  7280 

2b Pena D. Perez D. Guitian E. Castedo L. J. Am. Chem. Soc.  1999,  121:  5827 

2c Radhakrishnan KV. Yoshikawa E. Yamamoto Y. Tetrahedron Lett.  1999,  40:  7533 

2d Larock RC. Tian Q. J. Org. Chem.  1998,  63:  2002 

2e Feldman KS. Ruckle RE. Ensel SM. Weinreb PH. Tetrahedron Lett.  1992,  33:  7101 

3 Wakasugi K. Nishii Y. Tanabe Y. Tetrahedron Lett.  2000,  41:  5937 

4 Viswanathan GS. Wang M. Li CJ. Angew. Chem. Int. Ed.  2002,  41:  2138 

5 For a monograph, see: Raifeld YE. Raisman AM. Lee VJ. Asymmetric Epoxidation: Mechanisms, Techniques, and Synthetic Applications   CRC; Boca Raton, FL, USA: 1999. 

6a Li J. Li CJ. Tetrahedron Lett.  2001,  42:  793 

6b Ranu BC. Jana U. J. Org. Chem.  1998,  63:  8212 

For recent leading examples of GaCl₃ catalyzed reactions, see:

7a Yonehara F. Kido Y. Morita S. Yamaguchi M. J. Am. Chem. Soc.  2001,  123:  11310 

7b Kido Y. Yonehara F. Yamaguchi M. Tetrahedron  2001,  57:  827 

7c Takaya J. Kagoshima H. Akiyama T. Org. Lett.  2000,  2:  1577 ; and references cited therein

7d Asao N. Asano T. Ohishi T. Yamamoto Y. J. Am. Chem. Soc.  2000,  122:  4817 

7e Kido Y. Yoshimura S. Yamaguchi M. Uchimaru T. Bull. Chem. Soc. Jpn.  1999,  72:  1445 

7f Su J. Goodwin SD. Li XW. Robinson GH. J. Am. Chem. Soc.  1998,  120:  12994 

7g Kido Y. Yamaguchi M. J. Org. Chem.  1998,  63:  8086 

8 Viswanathan GS. Li CJ. Tetrahedron Lett.  2002,  43:  1613 

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%).