Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA.
J Am Chem Soc. 2010 May 5;132(17):6001-5. doi: 10.1021/ja9063074.
The intramolecular alpha-arylation of aldehydes via organo-SOMO catalysis was investigated using density functional theory (B3LYP and M06-2X functionals). The geometries, spin densities, Mulliken charges, and molecular orbitals of the reacting enamine radical cations were analyzed, and the nature of the resulting cyclized radical cation intermediates was characterized. In agreement with experimental observations, the calculated 1,3-disubstituted aromatic system shows ortho selectivity, while the 1,3,4-trisubstituted systems show para, meta (instead of ortho, meta) selectivity. The selectivity change for the trisubstituted rings is attributed to a distortion of the ortho substituents in the ortho, meta cyclization transition structures that causes a destabilization of these isomers and therefore results in selectivity for the para, meta product.
通过有机 SOMO 催化研究了醛的分子内 α-芳基化反应，使用了密度泛函理论（B3LYP 和 M06-2X 泛函）。分析了反应烯胺自由基阳离子的几何形状、自旋密度、Mulliken 电荷和分子轨道，以及所得环状自由基阳离子中间体的性质。与实验观察结果一致，计算出的 1,3-二取代芳体系表现出邻位选择性，而 1,3,4-三取代体系表现出对位、间位（而不是邻位、间位）选择性。对于三取代环的选择性变化归因于邻位取代基在邻位、间位环化过渡态中的扭曲，导致这些异构体的不稳定，从而导致对位、间位产物的选择性。
