Controlling Axial Conformation in 2-Arylpyridines and 1-Arylisoquinolines: Application to the Asymmetric Synthesis of QUINAP by Dynamic Thermodynamic Resolution
Controlling Axial Conformation in 2-Arylpyridines and 1-Arylisoquinolines: Application to the Asymmetric Synthesis of QUINAP by Dynamic Thermodynamic Resolution
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DOI：
10.1021/ja900722q
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发表时间：
2009-04-15
影响因子：
15
通讯作者：
Rowbottom, Stephen J. M.
中科院分区：
文献类型：
--
作者：
Clayden, Jonathan;Fletcher, Stephen P.;Rowbottom, Stephen J. M.
与相关的联苯化合物不同，2-芳基吡啶和1-芳基异喹啉可以通过在Ar-Ar键附近的亚砜基取代基的存在而优先采用两种轴向构象之一。在取代较多的双芳基的情况下，化合物是异位异构的，并且加热时可以获得约4:1的热力学选择性。在阻碍较少的化合物的情况下，可以实现高达20:1的构象比。通过实验与理论比较，推导出了优选构象。在热力学控制下，亚砜诱导的构象偏好可以在不对称合成中被利用，包括配体QUINAP。
Unlike related biphenyl compounds, 2-arylpyriclines and 1-arylisoquinolines can be induced to adopt preferentially one of two axial conformations by the presence of a sulfinyl substituent adjacent to the Ar-Ar bond. In the case of more substituted biaryls, the compounds are atropisomeric, and thermodynamic selectivities of about 4:1 may be attained on heating. In the case of less hindered compounds, conformer ratios of up to 20:1 may be achieved. Preferred conformations are deduced by comparison of experimental CD spectra with those derived from theory. The conformational preferences induced by the sulfoxides may be exploited in the asymmetric synthesis of atropisomers, including the ligand QUINAP, by dynamic resolution under thermodynamic control.