Synfacts 2010(5): 0523-0523  
DOI: 10.1055/s-0029-1219723
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart ˙ New York

Palladium-Catalyzed Synthesis of Five-Membered Heterocycles from 1,6-Enynes

Contributor(s): Victor Snieckus, Alcides da Silva
T.-j. Meng, Y. Hu*, S. Wang*
Anhui Normal University, Wuhu and Shanghai Institute of Organic Chemistry, P. R. of China
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Publikationsverlauf

Publikationsdatum:
22. April 2010 (online)

Significance

An efficient method for the construction of five-membered aromatic (3) and nonaromatic (4) heterocycles by a palladium-catalyzed coupling-cycloisomerization of 1,6-enynes with aryl halides has been developed. The ­reaction conditions using benzenesulfonamide (1, X = NTs) and (2, R² = 4-EtO2C) were optimized. The scope and limitations of this methodology were investigated. The reaction of the aryl halides having electron-withdrawing groups, such as CO2R, COMe, CHO, Cl, SO2Me, and CN gave the five-membered heterocycles in moderate to good yields. However, systems bearing electron-donating substituents, e.g. 4-Me and 4-MeO, did not afford the corresponding five-membered heterocycles. A mechanism for the formation of both aromatic and nonaromatic products was proposed.