Chemoselective Michael Type Addition of Aliphatic Amines to α,β-Ethylenic Compounds Using Bismuth Triflate Catalyst

Abstract

Catalytic amounts of bismuth triflate efficiently catalyse the conjugate addition of aliphatic amines to α,β-ethylenic compounds in acetonitrile under mild conditions. The reaction is chemoselective, as aromatic amines do not participate in the reaction. Further, the catalyst can be easily recovered and reused.

Michael addition - bismuth triflate - aliphatic amines - α,β-ethylenic compounds - chemoselectivity

References

1 Ben Ayed T. Amiri H. El Gaied MM. Villieras J. Tetrahedron  1995,  35:  9633 ; and references cited therein

2 Pfau M. Bull. Soc. Chim. France  1967,  117 

3 Perlmutter P. Conjugate Addition Reaction in Organic synthesis   Pergamon Press; Oxford: 1992. 

4 Furukawa M. Okawara T. Terawaki Y. Chem. Pharm. Bull.  1977,  25:  1319 

5 D’Angelo J. Maddaluno J. J. Am. Chem. Soc.  1986,  108:  8112 

6 Jenner G. Tetrahedron Lett.  1995,  36:  233 

7 Matsubara S. Yoshioka M. Utimoto K. Chem. Lett.  1994,  827 

8 Shaikh SN. Deshpande HV. Bedekar AV. Tetrahedron  2001,  57:  9045 

9a Suzuki H. Ikegami T. Matano Y. Synthesis  1997,  249 

9b Marshall JA. Chemtracts  1997,  10:  1064 

9c Vidal S. Synlett  2001,  1194 

9d Desmurs JR. Labrouillere M. Le Roux C. Gaspard H. Laporterie A. Dubac J. Tetrahedron Lett.  1997,  38:  8871 

9e Repichet S. Le Roux C. Dubac J. Eur. J. Org. Chem.  1998,  2743 

9f Repichet S. Le Roux C. Hernandez P. Dubac J. Desmurs JR. J. Org. Chem.  1999,  64:  6479 

9g Repichet S. Le Roux C. Dubac J. Tetrahedron Lett.  1999,  40:  9233 

9h Laurent-Robert H. Le Roux C. Dubac J. Synlett  1998,  1138 

9i Garrigues B. Gonzaga F. Robert H. Dubac J. J. Org. Chem.  1997,  62:  4880 

9j Robert H. Garrigues B. Dubac J. Tetrahedron Lett.  1998,  39:  1161 

9k Yanagisawa A. Morodome M. Nakashima H. Yamamoto H. Synlett  1997,  1309 

9l Choudary BM. Chidara S. Rajasekar CV. Synlett  2002,  1694 

10 Varala R. Alam MM. Adapa SR. Synlett  2003,  67 

11

General procedure for the Michael addition of Methyl-(3-pyrrolidine)-propionate(1). A mixture of pyrrolidine (0.2 mL, 2.3 mmol), methyl acrylate (0.414 mL, 4.6 mmol) and bismuth triflate (2 mol%) in anhydrous acetonitrile (5 mL) was kept at ambient temperature under vigorous stirring for 30 min. After completion of the reaction as indicated by TLC, the reaction mixture was filtered and catalyst was separated out, reaction mixture was extracted with ethyl acetate and purified by using column chromatography on silica gel to obtain pure product all most in quantitative yield. Similar experimental procedures have been carried out for other substrates and their chemical yields of isolated products are summarized in Table [1] . All isolated compounds were fully characterized by comparing their physical data (¹H NMR, Mass Spectra, IR) of authentic compounds.