1401051-85-1Relevant articles and documents
Rhodium-catalyzed cascade oxidative annulation leading to substituted naphtho[1,8- bc ]pyrans by sequential cleavage of C(sp2)-H/C(sp 3)-H and C(sp2)-H/O-H Bonds
Tan, Xing,Liu, Bingxian,Li, Xiangyu,Li, Bin,Xu, Shansheng,Song, Haibin,Wang, Baiquan
supporting information, p. 16163 - 16166 (2012/11/07)
The cascade oxidative annulation reactions of benzoylacetonitrile with internal alkynes proceed efficiently in the presence of a rhodium catalyst and a copper oxidant to give substituted naphtho[1,8-bc]pyrans by sequential cleavage of C(sp2)-H/C(sp3)-H and C(sp2)-H/O-H bonds. These cascade reactions are highly regioselective with unsymmetrical alkynes. Experiments reveal that the first-step reaction proceeds by sequential cleavage of C(sp2)-H/C(sp3)-H bonds and annulation with alkynes, leading to 1-naphthols as the intermediate products. Subsequently, 1-naphthols react with alkynes by cleavage of C(sp2)-H/O-H bonds, affording the 1:2 coupling products. Moreover, some of the naphtho[1,8-bc]pyran products exhibit intense fluorescence in the solid state.