Synthesis 2019; 51(13): 2729-2736
DOI: 10.1055/s-0037-1611519
paper
© Georg Thieme Verlag Stuttgart · New York

Gold(III)/Sodium Diphenylphosphinobenzene-3-sulfonate (TPPMS) Catalyzed Dehydrative N-Benzylation of Electron-Deficient Anilines in Water

,
Mika Matsumoto
,
Sayoko Tawara
,
,
Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan   eMail: hidemasa.hikawa@phar.toho-u.ac.jp   eMail: isao.azumaya@phar.toho-u.ac.jp
› Institutsangaben
This work was supported by JSPS KAKENHI Grant Number 16K08179.
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Publikationsverlauf

Received: 22. Februar 2019

Accepted after revision: 26. März 2019

Publikationsdatum:
17. April 2019 (online)


Abstract

A strategy for the dehydrative N-benzylation of electron-deficient anilines in water has been developed. The gold(III)/sodium diphenylphosphinobenzene-3-sulfonate (TPPMS) catalyst is highly effective as a Lewis acid for the activation of alcohols and tolerates aerobic conditions. A Hammett study in the reaction of para-substituted benzhydryl alcohols shows negative σ values, indicating a build-up of cationic charge during the rate-determining sp3 C–O bond-cleavage step. The inverse kinetic solvent isotope effect (KSIE = 0.6) is consistent with a specific acid catalysis mechanism. This simple protocol can be performed under mild conditions in an atom-economic process without the need for base or other additives, furnishing the electron-deficient N-benzylic anilines in moderate to excellent yields along with water as a sole coproduct.

Supporting Information