Incorporation of norbornene moiety onto the arene of diaryl substituted amides through C-H functionalization.

In the presence of norbornene, Pd(OAc) 2 smoothly catalyzed the meta -C-H activation process of N-phenylbenzamide ( 4 ) and yielded a norbornene fused product, (1 R ,4 S ,4a R ,8b S )-N-phenyl-1,2,3,4,4a,8b-hexahydro-1,4-methanobiphenylene-5-carboxamide ( 5a ). The employment of Ag(OAc) is crucial to the success of this reaction. Norbornene related compounds, dicyclopentadiene and norbordiene, were used as the reagents and structurally similar compounds, 5b and 5c were formed although with much lower yields. Similar reaction was carried out for using N-benzylbenzamide ( 9 ) as starting reagent. The resulted norbornene fused product (1R,4S,4aR,8bS)-N-benzyl-1,2,3,4,4a,8b-hexahydro-1,4-methanobiphenylene-5-carboxamide ( 10 ) shows that the C-H activation indeed took place at the phenyl ring of acetophenone part rather than the benzyl side. Crystal structures of 5a , 5c and 10 were determined by X-ray diffraction methods. A reaction mechanism is proposed to account for the formation of 5a , which could be extended to describe the generation of other structurally related compounds as well. [ABSTRACT FROM AUTHOR]