Absolute asymmetric synthesis. I. Mechanism of the photochemical synthesis of nonracemic helicenes with circularly polarized light. Wavelength dependence of the optical yield of octahelicene
The influence of the chiral environment in the photosynthesis of enantiomerically enriched hexahelicene. A sudden change in the chirality of hexahelicene by a change in the temperature of a chiral crystalline medium
作者:W. J. C. Prinsen、W. H. Laarhoven
DOI:10.1002/recl.19951141108
日期:——
The enrichment of one of the enantiomers (P or M) of hexahelicene (3) synthesized by the photochemical cyclodehydrogenation of 2-styryl-benzo[c]phenanthrene (1) in chiral media has been (re)investigated. Four different chiral solvents, two cholesteric liquid crystals, two chiral crystals, all at several temperatures, and two chiral polymers were used as media. To avoid erroneous values from circular-dichroism
已经(重新)研究了2-苯乙烯基-苯并[ c ]菲(1)的光化学环脱氢合成的六庚烯(3)对映体之一(P或M)的富集。四种不同的手性溶剂,两种胆甾型液晶,两种手性晶体(均在几个温度下)和两种手性聚合物用作介质。为了避免由于手性副产物的贡献而导致的圆二色性(CD)测量值错误,通过HPLC分析确定对映体过量(ee)。
The structure of the dihydrohexahelicene formed by the irradiation of styryl benzo [c] phenanthrene under anaerobic conditions
According to Wismontski and Fischer irradiationunderanaerobicconditions of 2-styryl benzo [c]phenanthrene (1) gives rise to an isolable dihydrohexahelicene which is easily oxidized into hexahelicene. Its structure obviously different from 5,6-dihydrohexahelicene 4 waselucidated by the analysis of the 500 MHz-NMR spectrum. The structure and configuration: trans-6a, 16d-dihydrohexahelicene with the
Prinsen, W. J. C.; Laarhoven, W. H.; Bosman, W. P., Recueil des Travaux Chimiques des Pays-Bas, 1988, vol. 107, p. 575 - 582
作者:Prinsen, W. J. C.、Laarhoven, W. H.、Bosman, W. P.、Behm, H.、Beurskens, P. T.
DOI:——
日期:——
Contribution of pitch and solute-solvent interactions to the photoasymmetric synthesis of hexahelicene in cholesteric liquid crystals
作者:Marcel Hibert、Guy Solladie
DOI:10.1021/jo01314a044
日期:1980.12
Formation of 5,6- and 7,8-dihydrohexahelicene: mechanistic details of the rearrangement of the primary photocyclization product of 2-styrylbenzo[c]phenanthrene in the presence of a base