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Directed ortho-metalation versus reductive amination in the preparation of polytopic, highly substituted, and sterically congested amine-S-arylthiocarbamates as thiophenol precursors.
- Source :
-
Tetrahedron . Nov2013, Vol. 69 Issue 45, p9499-9506. 8p. - Publication Year :
- 2013
-
Abstract
- Abstract: The synthesis of polydentate amine-S-arythiocarbamates was tested by directed ortho-lithiation of 2,4-disubstituted thiophenols, or the corresponding O- and S-arylthiocarbamates by deprotonation or lithium–bromine exchange, followed by addition of the electrophiles N(CH2CH2X)3 (X=Br, I). In the case of the thiophenol, deprotonation resulted in a trithioether-amine upon addition of the electrophile. With the O- and S-thiocarbamates, the reactions resulted in the migration of the thiocarbamoyl group to the ortho-position (Fries rearrangement), or nucleophilic attack of the carbonyl group by butyllithium, respectively. An alternative route employed 2,4-disubstituted phenols to obtain the corresponding salicylaldehydes, and subsequently the O-arylthiocarbamates for Newman–Kwart thermal rearrangement (NKR). Finally, the formyl group on the S-arylthiocarbamates allowed reductive amination to assemble polytopic compounds with amine and S-thiocarbamate groups. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 00404020
- Volume :
- 69
- Issue :
- 45
- Database :
- Academic Search Index
- Journal :
- Tetrahedron
- Publication Type :
- Academic Journal
- Accession number :
- 90421433
- Full Text :
- https://doi.org/10.1016/j.tet.2013.08.044