synthetic strategy toward phosphahelicenes containing a terminal phosphinine ring has been explored. The 4-phenyl-6-methyl-2-phospha[7]helicene was prepared from starting 2-bromobenzo[c]phenanthrene in 12% overall yield in 12 steps. The synthetic approach involves introduction of the phosphorus function prior to photocyclization forming the final helicene skeleton, followed by the formation of a phosphorus
已经探索了针对含有末端膦环的磷酸螺旋烯的合成策略。4-phenyl-6-methyl-2-phospha[7]helicene 由起始 2-溴苯并[ c ]菲在 12 个步骤中以 12% 的总产率制备。合成方法包括在光环化形成最终的螺旋骨架之前引入磷功能,然后形成磷六环。通过 X 射线晶体学证实了具有末端膦环的第一个 phosphahelicene 的结构。
Synthesis and characterization of a new hexacyclic helicene
作者:Faouzi Aloui、Souad Moussa、Béchir Ben Hassine
DOI:10.1016/j.tetlet.2012.04.014
日期:2012.6
A new helically chiral hexacyclic system, bearing an acetoxymethyl group, was prepared from a simple naphthalene building block in good yield and purity, via a four-step sequence involving palladium-catalysed Heck couplings and oxidative photocyclizations. Suitable crystals of the latter indicate that its conformation closely resembles that of unsubstituted [6]helicene, whose idealized symmetry is C-2. The optical properties of the hexacyclic helicene were investigated and show interesting behaviour. (C) 2012 Elsevier Ltd. All rights reserved.