Synthesis 2012; 44(14): 2185-2194
DOI: 10.1055/s-0031-1291041
special topic
© Georg Thieme Verlag Stuttgart · New York

Lewis Acid Catalyzed Benzylic C–H Bond Functionalization of Azaarenes; Addition to Imines and Enones

Hirotomo Komai
a  Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, Fax: +81(3)56845206   Email: smatsuna@mol.f.u-tokyo.ac.jp   Email: kanai@mol.f.u-tokyo.ac.jp
,
Tatsuhiko Yoshino
a  Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, Fax: +81(3)56845206   Email: smatsuna@mol.f.u-tokyo.ac.jp   Email: kanai@mol.f.u-tokyo.ac.jp
,
Shigeki Matsunaga*
a  Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, Fax: +81(3)56845206   Email: smatsuna@mol.f.u-tokyo.ac.jp   Email: kanai@mol.f.u-tokyo.ac.jp
b  Kanai Life Science Catalysis Project, ERATO, Japan Science and Technology Agency, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
,
Motomu Kanai*
a  Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan, Fax: +81(3)56845206   Email: smatsuna@mol.f.u-tokyo.ac.jp   Email: kanai@mol.f.u-tokyo.ac.jp
b  Kanai Life Science Catalysis Project, ERATO, Japan Science and Technology Agency, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
› Author Affiliations
Further Information

Publication History

Received: 06 April 2012

Accepted: 10 April 2012

Publication Date:
14 May 2012 (eFirst)

Abstract

Lewis acid catalyzed benzylic C–H bond functionalization of alkyl-substituted azaarenes is described. The addition to N-tosyl imines proceeded under solvent-free conditions using various Lewis acids. Cu(OTf)2 was the best Lewis acid, and 1,2-addition proceeded at 60–120 °C, giving products in 23–92% yield. On the other hand, strongly Lewis acidic rare-earth metal triflates, Sc(OTf)3 and Y(OTf)3, were essential to promote the 1,4-addition of alkyl-substituted azaarenes to enones, and products were obtained in 60–96% yield.

 
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