Synlett 2004(7): 1321-1322  
DOI: 10.1055/s-2004-825600
SPOTLIGHT
© Georg Thieme Verlag Stuttgart · New York

Dimethyl(methylene)ammonium Salts: Mannich Reagents

Heedong Yun*
Department of Chemistry, Havemeyer Hall MC 3135, Columbia University, 3000 Broadway, New York, NY 10027, USA
e-Mail: hy2013@columbia.edu;
Further Information

Publication History

Publication Date:
10 May 2004 (online)

Introduction

These reagents comprise a family of preformed iminium salts which have been extensively utilized in condensation reactions with carbonyl and aromatic compounds in a variant of the Mannich reaction. Böhme prepared the first dimethyl(methylene)ammonium chloride (1), [1] and the ­iodide salt 2 was later developed by Eschenmoser. [2] Preformed iminium salts are sufficiently soluble in many aprotic solvents, enabling the use of highly reactive nucleophiles which ordinarily would decompose under the protic conditions of the classical Mannich reaction. A comparison study of these salts favors the trifluoroacetate salt (3) because it is the most soluble and can be transferred by syringe, although it is more tedious to prepare. [3]

Salt 1 is prepared by cleavage of N,N,N¢,N¢-tetramethylmethanediamine by AcCl [4] or cleavage of methyl dimethylaminomethyl ether by TMSCl. [5] Salt 2 is prepared by thermolysis of (iodomethyl)trimethylammonium iodide2 or cleavage of N,N,N¢,N¢-tetramethylmethanediamine by TMSI. [6] Salt 3 is prepared by Polonovski reaction of tri­methylamine oxide with TFAA or cleavage of N,N,N¢,N¢-tetramethylmethanediamine with TFA. [7]

    References

  • 1 Böhme H. Mundlos E. Herboth O.-E. Chem. Ber.  1957,  90:  2003 
  • 2 Schreiber J. Maag H. Hashimoto N. Eschenmoser A. Angew. Chem., Int. Ed. Engl.  1971,  10:  330 
  • 3 Holy N. Fowler R. Burnett E. Lorenz R. Tetrahedron  1979,  35:  613 
  • 4 Kinast . Tietze L.-F. Angew. Chem., Int. Ed. Engl.  1976,  15:  239 
  • 5 Robin C. Babot O. Dunogues J. Duboudin F. Synthesis  1986,  228 
  • 6 Bryson TA. Bonitz GH. Reichel CJ. Dardis RE. J. Org. Chem.  1980,  45:  524 
  • 7 Ahond A. Cave A. Kan-Fan C. Husson H.-P.
    de Rostolan
    J. Potier P. J. Am. Chem. Soc.  1968,  90:  5622 
  • 8 Danishefsky S. Prisbylla M. Lipisko B. Tetrahedron Lett.  1980,  805 
  • 9 Hooz J. Bridson JN. J. Am. Chem. Soc.  1973,  95:  602 
  • 10 Gagnon A. Danishefsky SJ. Angew. Chem. Int. Ed.  2002,  41:  1581 
  • 11 Pochini A. Puglia G. Ungaro R. Synthesis  1983,  906 
  • 12 Cooper MS. Fairhurst RA. Heaney H. Papageorgiou G. Wilkins RF. Tetrahedron  1989,  45:  1155 
  • 13 Holy NL. Synth. Commun.  1976,  539 
  • 14 Germon C. Alexakis A. Normant JF. Bull. Soc. Chim. France  1984,  II-377 
  • 15 Poulter CD. Roberts JL. Borromeo PS. Tetrahedron Lett.  1977,  1299 
  • 16 Böhme H. Martin F. Chem. Ber.  1973,  106:  3540 
  • 17 Unterhalt B. Koehler H. Synthesis  1977,  265