Synlett
DOI: 10.1055/s-0036-1588442
cluster
© Georg Thieme Verlag Stuttgart · New York

Boron-Catalyzed Hydrogenative Reduction of Substituted Quinolines to Tetrahydroquinolines with Hydrosilanes

Narasimhulu Gandhamsettya, b, Sehoon Park*a, b, Sukbok Chang*a, b
  • aCenter for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 305-701, South Korea
  • bDepartment of Chemistry, Korea Advanced Institute of Science & Technology (KAIST), Daejeon 305-701, South Korea   Email: sehoonp@kaist.ac.kr   Email: sbchang@kaist.ac.kr
This research was supported by the Institute for Basic Science (IBS-R010-D1) in Korea.
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Publication History

Received: 30 March 2017

Accepted after revision: 09 May 2017

Publication Date:
23 May 2017 (eFirst)

Published as part of the Cluster Silicon in Synthesis and Catalysis

Abstract

A metal-free procedure for the hydrogenative reduction of substituted N-heteroaromatics has been developed by using hydrosilanes as reducing agents. The optimized conditions were successfully applied to the reactions of quinolines, quinoxalines, and quinoline N-oxides. They were also effective for the reduction of quinolines bearing amino or hydroxy groups, where H2 was evolved through dehydrogenative silylation of the amine or hydroxy moieties. Preliminary mechanistic studies revealed that the initial step in the catalytic cycle involves 1,4-addition of the hydrosilane to the quinoline to give a 1,4-dihydroquinoline; this is followed by (transfer) hydrogenation to deliver the tetrahydroquinoline as the final product.

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