Expeditious synthesis of helicenes using an improved protocol of photocyclodehydrogenation of stilbenes
作者:Harish R. Talele、Anju R. Chaudhary、Parthiv R. Patel、Ashutosh V. Bedekar
DOI:10.3998/ark.5550190.0012.902
日期:——
developed for photodehydrocyclization of stilbenes for the synthesis of phenanthrenes and helicenes. This procedure involves the use of THF as a scavenger of hydriodicacid produced during iodine mediated photodehydrocyclization. The use of THF is advantageous due to its higher boiling point, lower cost and easy availability as compared to propylene oxide. The method is applied to synthesize a number
The synthesis of 2-bromo[6]helicene was revised and improved up to 51% yield. Its reactivity was thoroughly investigated, and a library of 17 different carbon, boron, nitrogen, phosphorus, oxygen and sulfur substituted derivatives was prepared. The racemization barrier for 2-bromo[6]helicene was determined, and the usage of enantiomers in the synthesis of optically pure helicenes was rationalized.
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。
Janke, Roland; Haufe, Guenter, Russian Journal of Organic Chemistry, 1994, vol. 30, # 9.2, p. 1432 - 1434
作者:Janke, Roland、Haufe, Guenter
DOI:——
日期:——
Hexahelicene. Absolute configuration
作者:David A. Lightner、Daniel T. Hefelfinger、Thomas W. Powers、Gerard W. Frank、Kenneth N. Trueblood