Eco-friendly N-acyliminium ion chemistry: solvent-free HNTf2 and TIPSOTf-catalyzed α-amidoalkylation of silicon-based π-nucleophiles

Tetrahedron Letters

Volumn 47, Issue 26, 2006, Pages 4477-4480

  Tranchant, Marie José ^a   Moine, Charlotte ^a   Othman, Raja Ben ^a   Bousquet, Till ^a   Othman, Mohamed ^a   Dalla, Vincent ^a  

^a UNIVERSITÉ DU HAVRE   (France)

Author keywords

[No Author keywords available]

Indexed keywords

IMINE; N ACYLIMINIUM ION; PI NUCLEOPHILE; SILICON; SOLVENT; UNCLASSIFIED DRUG;

ALKYLATION; ARTICLE; CATALYSIS; CATALYST; CHEMISTRY;

EID: 33646758214     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetlet.2006.04.090     Document Type: Article

References (29)

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26. 7f.
27. Unpublished results from our group.
28. 2 or TIPSOTf, a white precipitate rapidly appeared and no reaction occurred. However, the corresponding Mannich product could be obtained in a correct yield of 64% by performing the reaction in dichloromethane under forced conditions, that is, by using 20 mol % of TIPSOTf and 4 equiv of the silyl enol ether within a long reaction period of 20 h. The nucleophilicity of this enol ether is not reported in the Mayr's scale, but can be compared to that of the trimethylsilyl enol ether of acetone, which is slightly inferior to that of the trimethylsilyl enol ether of acetophenone. Allyltrimethylsilane, however, considerably lacks nucleophilicity for addition to the iminium cation.
29. As this work was in progress, Matsumara and co-workers reported that the Mannich reaction between N,O-acetals and methylene actives catalyzed by 10 mol % of various Brønsted- and Lewis acids under solvent-free conditions proceeded with more efficiency than those carried out in dichloromethane. Matsumara Y., Ikeda T., and Onomura O. Heterocycles 67 (2006) 113