Müller Christian, Pidko Evgeny A, Staring Antonius J P M, Lutz Martin, Spek Anthony L, van Santen Rutger A, Vogt Dieter
Department of Chemical Engineering and Chemistry, Schuit Institute of Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
Chemistry. 2008;14(16):4899-905. doi: 10.1002/chem.200800175.
Both enantiomers of the first atropisomeric phosphinine (1) have been isolated by using analytical HPLC on a chiral stationary phase. The enrichment of one enantiomer and a subsequent investigation into its racemization kinetics revealed a barrier for internal rotation of DeltaG(298)(double dagger) = (109.5+/-0.5) kJ mol(-1), which is in excellent agreement with the theoretically predicted value of DeltaG(298)(double dagger) =116 kJ mol(-1). Further analysis with UV and circular dichroism spectroscopies and density functional theory calculations led to the determination and assignment of the absolute configurations of both enantiomers. These results are the basis for future investigations into this new class of axially chiral phosphinine-based ligands and their possible applications in asymmetric homogeneous catalysis.
通过在手性固定相上使用分析型高效液相色谱法，已分离出首个阻转异构膦宁（1）的两种对映体。对其中一种对映体的富集以及随后对其消旋动力学的研究表明，内旋转能垒为ΔG(298)‡ = (109.5±0.5) kJ mol⁻¹，这与理论预测值ΔG(298)‡ = 116 kJ mol⁻¹ 非常吻合。通过紫外光谱、圆二色光谱以及密度泛函理论计算进行的进一步分析，确定并指定了两种对映体的绝对构型。这些结果为今后对这类新型轴向手性膦宁基配体及其在不对称均相催化中可能应用的研究奠定了基础。
