State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
J Am Chem Soc. 2012 Oct 3;134(39):16163-6. doi: 10.1021/ja3075242. Epub 2012 Sep 25.
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(sp(2))-H/C(sp(3))-H and C(sp(2))-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(sp(2))-H/C(sp(3))-H bonds and annulation with alkynes, leading to 1-naphthols as the intermediate products. Subsequently, 1-naphthols react with alkynes by cleavage of C(sp(2))-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.
在铑催化剂和铜氧化剂的存在下，苯乙腈与内部炔烃的级联氧化环化反应高效进行，通过连续断裂 C(sp(2))-H/C(sp(3))-H 和 C(sp(2))-H/O-H 键，生成取代的萘并[1,8-bc]吡喃。这些级联反应具有高度的区域选择性，对于不对称炔烃也是如此。实验表明，第一步反应通过连续断裂 C(sp(2))-H/C(sp(3))-H 键和与炔烃的环化反应进行，得到 1-萘酚作为中间体产物。随后，1-萘酚通过 C(sp(2))-H/O-H 键的断裂与炔烃反应，得到 1:2 偶联产物。此外，一些萘并[1,8-bc]吡喃产物在固态下表现出强烈的荧光。
