Synthesis of Naphthalenes and 2-Naphthols by the Electrophilic Cyclization of Alkynes
作者:Xiaoxia Zhang、Sampa Sarkar、Richard C. Larock
DOI:10.1021/jo051948k
日期:2006.1.1
variety of substituted naphthalenes are readily prepared regioselectively under mild reaction conditions by the 6-endo-dig electrophiliccyclization of appropriate arene-containing propargylic alcohols by ICl, I2, Br2, NBS, and PhSeBr. 3-Iodo-2-naphthols have also been prepared in excellent yields by the cyclization of analogous 1-aryl-3-alkyn-2-ones. This methodology readily accommodates various functional
sila[n]helicenes via dehydrogenativesilylation of C–H bonds. By selecting the proper ligands, the current method provides the ability to prepare unsymmetrical sila[n]helicene derivatives without any oxidants. The resulting sila[6]helicene is a rare example of a five-membered ring-fused [6]helicene, which was isolated as a single pure enantiomer without substituents on the terminal benzene rings.
使用具有(R)-(S)-BPPFA配体的铑催化剂,可通过C-H键的脱氢甲硅烷基化反应有效合成sila [ n ] hellicenes。通过选择合适的配体,当前方法提供了在没有任何氧化剂的情况下制备不对称甲硅烷基[ n ]]烯衍生物的能力。所得的硅[ 6 ]螺旋烯是五元环稠合的[ 6 ]螺旋烯的稀有实例,其被分离为单个纯对映体,末端苯环上没有取代基。
Photocyclisations of 1,4-diarylbut-1-en-3-ynes. Part III. Scope and limitations of the reaction
作者:Alois H. A. Tinnemans、Wim H. Laarhoven
DOI:10.1039/p29760001115
日期:——
The photoreactivity of a large series of diarylbutenynes has been studied in order to establish the scope of this photocyclisationreaction. The conditions for an optimal yield of photocyclisation products are discussed. On addition of iodine to the butenyne solution, irradiation gives rise to iodo-derivatives of the normal cyclisation products, whereas in the presence of iodine and with benzene as