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Access to Sondheimer-Wong Diyne-Embedded Diaza[7]helicene with High Dissymmetry Factor Via Spontaneous Valence
Guanxing Zhu1, Tingting Ding1, Hailong Chen1
1Jiangsu Provincial Key Laboratory of Biomanufacturing of Chiral Pharmaceutical Chemicals, Taizhou University, Jichuan Road 93, Taizhou, 225300, P. R. China.
Abstract:
The synthesis of Sondheimer-Wong diyne-fused diaza[7]helicene was achieved through spontaneous valence isomerization, which was a key step. Crystallographic analysis resolved the diaza[7]helicene's absolute configuration. The P,P- and M,M-enantiomers were separated by chiral HPLC and further characterized by CD and CPL spectroscopy. The obtained aza[7]helicene shows high dissymmetry factors with a gabs of 0.046 (608 nm) and a glum of 0.0138 (693 nm). Theoretical calculation revealed that the Sondheimer-Wong diyne integration suppressed |μ| and enhanced |m| resulting in the high g factor.
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