Synthesis 2006(3): 489-495  
DOI: 10.1055/s-2006-926278
PAPER
© Georg Thieme Verlag Stuttgart · New York

Synthesis of C6F5-Substituted Aminoethanols via Acetate Ion Mediated C6F5-Group Transfer Reaction

Vitalij V. Levina, Alexander D. Dilman*a, Pavel A. Belyakova, Alexander A. Korlyukovb, Marina I. Struchkovaa, Mikhail Y. Antipinb, Vladimir A. Tartakovskya
a N. D. Zelinsky Institute of Organic Chemistry, Leninsky Prosp. 47, 119991 Moscow, Russian Federation
Fax: +7(95)1355328; e-Mail: adil25@mail.ru;
b A. N. Nesmeyanov Institute of Organoelement Compounds, Vavilov Str. 28, 119991 Moscow, Russian Federation
Further Information

Publication History

Received 15 June 2005
Publication Date:
11 January 2006 (online)

Abstract

A new approach for the synthesis of N-(pentafluorophen­ylmethyl)aminoethanols is developed. The method includes alkyl­ation of imines with 2-tris(pentafluorophenyl)silyloxyethyl triflate, prepared from ethylene oxide and (C6F5)3SiOTf, to give 2-silyloxyethyliminium ions. Their treatment with sodium acetate induces C-C bond formation proceeding as transfer of the C6F5 group from the five-coordinate silicate intermediate to the iminium center.

    References

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8

When N-methyl-C-phenylimine (2a) was combined with (C6F5)3SiOTf in CDCl3 no silyl iminium ion was observed (1H, 19F NMR control). Correspondingly, it is believed that silyl iminium ion from 2b and (C6F5)3SiOTf is formed in small equilibrium concentration.

9

In the absence of pyridine lower yields of 4 were achieved, presumably owing to oligomerization of ethylene oxide by traces of triflic acid.

15

NaOAc is insoluble in THF. However, it dissolves in reaction mixture as C6F5 group transfer occurs, thereby allowing for convenient monitoring of reaction progress.

16

Crystallographic data (excluding structure factors) have been deposited with the Cambridge Crystallographic Data Centre, CCDC 275041 (for 4) and 275042 (for 3c) and are available free of charge at CCDC, 12 Union Road, Cambridge CB2 1EZ, UK [fax: +44 (1223)336033 or e-mail: deposit@ccdc.cam.ca.uk].