Synlett 2015; 26(13): 1885-1889
DOI: 10.1055/s-0034-1380220
letter
© Georg Thieme Verlag Stuttgart · New York

Palladium(II)-Catalyzed C–H Activation and C–C Coupling/Cyclization of Benzamidine and Terminal Alkynes Using an Internal Oxidant

Xu Zhang*
School of Chemistry and Pharmacony Engineering, Nanyang Normal University, Nanyang 473061, P. R. of China   Email: zhangxuedu@126.com
,
Xuefeng Xu
School of Chemistry and Pharmacony Engineering, Nanyang Normal University, Nanyang 473061, P. R. of China   Email: zhangxuedu@126.com
,
Yingke Wu
School of Chemistry and Pharmacony Engineering, Nanyang Normal University, Nanyang 473061, P. R. of China   Email: zhangxuedu@126.com
,
Zhiqiang Wang
School of Chemistry and Pharmacony Engineering, Nanyang Normal University, Nanyang 473061, P. R. of China   Email: zhangxuedu@126.com
,
Lintao Yu
School of Chemistry and Pharmacony Engineering, Nanyang Normal University, Nanyang 473061, P. R. of China   Email: zhangxuedu@126.com
,
Qiang Zhao
School of Chemistry and Pharmacony Engineering, Nanyang Normal University, Nanyang 473061, P. R. of China   Email: zhangxuedu@126.com
,
Fu Shi
School of Chemistry and Pharmacony Engineering, Nanyang Normal University, Nanyang 473061, P. R. of China   Email: zhangxuedu@126.com
› Author Affiliations
Further Information

Publication History

Received: 11 March 2015

Accepted after revision: 22 April 2015

Publication Date:
09 July 2015 (online)


Abstract

Herein, an efficient palladium(II)-catalyzed C–C coupling/cyclization reaction by directed C–H activation of benzamidine and terminal alkynes has been developed. In this practical and high-yielding process, the C–N bond acts as an internal oxidant. It was found that molecules with both electron-donating and electron-withdrawing substituents were suitable substrates for this transformation, and the expected products were obtained in moderate to excellent yields, but when the benzamidine with ortho-methyl substituent is employed, the benzamidine compound may undergo the [1,5]-hydrogen migration, and then Diels–Alder reaction with terminal alkynes to produce the quinoline compound. The use of a single catalytic system to mediate chemical transformations in a synthetic operation is efficient in building complex structures from simple starting materials in an environmentally benign fashion.

Supporting Information