Synthesis 2019; 51(16): 3091-3100
DOI: 10.1055/s-0037-1610710
paper
© Georg Thieme Verlag Stuttgart · New York

A Highly Efficient Heterogeneous Copper-Catalyzed Oxidative Cyclization of Benzylamines and 1,3-Dicarbonyl Compounds To Give Trisubstituted Oxazoles

Li Wei
a   Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Chemistry & Chemical Engineering, Jiangxi Normal University, Nanchang 330022, P. R. of China   Email: mzcai@jxnu.edu.cn
,
Shengyong You*
b   Institute of Applied Chemistry, Jiangxi Academy of Sciences, Nanchang 330029, P. R. of China   Email: ysygood1981@163.com
,
Yuxin Tuo
a   Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Chemistry & Chemical Engineering, Jiangxi Normal University, Nanchang 330022, P. R. of China   Email: mzcai@jxnu.edu.cn
,
a   Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Chemistry & Chemical Engineering, Jiangxi Normal University, Nanchang 330022, P. R. of China   Email: mzcai@jxnu.edu.cn
› Author Affiliations
We thank the National Natural Science Foundation of China (No. 21462021), the Natural Science Foundation of Jiangxi Province (No. 20161BAB203086), and the Ministry of Education (Key Laboratory of Functional Small Organic Molecules, No. KLFS-KF-201704) for financial support.
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Publication History

Received: 24 February 2019

Accepted after revision: 02 April 2019

Publication Date:
02 May 2019 (online)


Abstract

The heterogeneous copper-catalyzed cascade oxidative cyclization between benzylamines and 1,3-dicarbonyl compounds was achieved by using the 3-(2-aminoethylamino)propyl-functionalized MCM-41-immobilized copper(II) complex [MCM-41-2N-Cu(OAc)2] as catalyst and t-BuOOH (TBHP) as oxidant, with iodine as additive, under mild conditions, yielding a wide variety of 2,4,5-trisubstituted oxazoles in mostly good to excellent yields. This heterogeneous copper catalyst can be facilely prepared via a simple two-step procedure from readily available and inexpensive reagents and exhibits a slightly higher activity than Cu(OAc)2. MCM-41-2N-Cu(OAc)2 is also easy to recover and can be recycled up to eight times with almost consistent activity. The reaction is the first example of heterogeneous copper-catalyzed intermolecular cyclization for the construction of polysubstituted oxazoles.

Supporting Information