Synthesis of Fluorinated Indolizines and 4H-Pyrrolo[1,2-a]benzimidazoles via 1,3-Dipolar Cycloaddition of Fluoroalkenes to N-Ylides

Abstract

In the presence of K₂CO₃ and Et₃N, pyridinium, quinolinium, isoquinolinium and benzimidazolinium N-ylides, generated in situ from their halides, react with gaseous flouroalkenes [CF₂=CFX (1), X = Cl (a), Br (b), CF₃ (d)] in DMF under atmos­pheric pressure in normal glassware at 70 °C to give the corresponding fluorinated indolizines or H-pyrrolo[1,2-a]benzimidazoles via 1,3-dipolar [3+2] cycloaddition. Similar results are obtained with tetrafluoroethene in an autoclave.

Key words

1,3-dipolar addition - [3+2] cycloaddition - fluoroalkene - fluorinated indolizine - fluorinated H-pyrrolo[1,2-a]benzimidoazole

References

• 1a Flitsch W. Comprehensive Heterocyclic Chemistry   Vol 4:  Katritzky AR. Rees CW. Pergamon; Oxford: 1984.  p.443 
• 1b Gubin J. Lucchetti J. Mahaux J. Nisato D. Rosseels G. Chinet M. Polster P. Chatelain P. J. Med. Chem.  1992,  35:  981 
• 1c Nugent RA. Murphy M. J. Org. Chem.  1987,  52:  2206 
• 1d Gubin J. Vogelear H. Inion H. Houben C. Lucchetti J. Mahaux J. Nisato D. Rosseels G. Chinet M. Polster P. Chatelain P. J. Med. Chem.  1993,  36:  142 
• 1e Harrell WB. Doerge RF. J. Pharm. Sci.  1967,  56:  225 
• 2a Skibo EB. Curr. Med. Chem.  1996,  3:  47 
• 2b Anisimova VA. Spasov AA. Bocharova IA. Ostrovskii OV. Panchenko TI. Dudchenko GP. Khim. Farm. Zh.  1996,  30:  22 ; Chem. Abstr. 1996, 124, 219939
• 3a Hudlicky M. Chemistry of Organic Fluorine Compounds   Ellis Horword; New York: 1976. 
• 3b Banks RE. Organoflurine Compounds and Their Applications   Ellis Horword; New York: 1979. 
• 4a Banks RE. Pritchard RG. Thomson J. J. Chem. Soc., Perkin Trans. 1  1986,  1769 
• 4b Banks RE. Mohialdin SN. J. Fluorine Chem.  1986,  34:  275 
• 4c Banks RE. Khaffaff SN. J. Fluorine Chem.  1991,  51:  407 
• 4d Banks RE. Khaffaff SN. J. Fluorine Chem.  1988,  38:  289 
• 5a Wu K. Chen QY. Chin. J. Chem.  2001,  19:  1273 ; Chem. Abstr. 2002, 136, 233853
• 5b Wu K. Chen QY. Tetrahedron  2002,  58:  4077 
• 6a Ogura H. Kikuchi K. J. Org. Chem.  1972,  37:  2679 
• 6b Matsuda Y. Heterocycles  1992,  33:  295 
• 7 These salts were synthesized according to the known procedure: Coe DG. J. Org. Chem.  1959,  24:  882