Lunazzi Lodovico, Mancinelli Michele, Mazzanti Andrea
Department of Organic Chemistry A. Mangini, University of Bologna, Viale Risorgimento 4, Bologna 40136, Italy.
J Org Chem. 2009 Feb 6;74(3):1345-8. doi: 10.1021/jo802383s.
Anthraquinone substituted by 2-methyl-1-naphthyl groups in positions 1,8 yields syn (meso) and anti (racemic) isomers (red and yellow colored, respectively) that interconvert with a barrier of 35.4 kcal mol(-1) in solution. Their structures were identified by NOE experiments in solution and X-ray diffraction in the solids. The racemic anti form (C(2) point group) entails two atropisomers that were separated by enantioselective HPLC: the absolute configuration was assigned by TD-DFT simulation of the ECD spectrum. Two atropisomers were also separated and assigned in the case of anthraquinone bearing a single 2-methyl-1-naphthyl substituent in position 1.
在1,8位被2-甲基-1-萘基取代的蒽醌会产生顺式（内消旋）和反式（外消旋）异构体（分别为红色和黄色），它们在溶液中以35.4千卡·摩尔⁻¹的势垒相互转化。通过溶液中的NOE实验和固体中的X射线衍射确定了它们的结构。外消旋反式异构体（C₂点群）包含两种阻转异构体，通过对映选择性高效液相色谱法将其分离：通过ECD光谱的TD-DFT模拟确定了绝对构型。对于在1位带有单个2-甲基-1-萘基取代基的蒽醌，也分离并确定了两种阻转异构体。
