Synthesis of Benzimidazoles by PIDA-Promoted Direct C(sp<sup>2</sup>)H Imidation of<i>N</i>-Arylamidines
作者:Jinbo Huang、Yimiao He、Yong Wang、Qiang Zhu
DOI:10.1002/chem.201202271
日期:2012.10.29
A metal‐free synthesis of diversified benzimidazoles from N‐arylamidines through a phenyliodine(III) diacetate (PIDA) promoted intramolecular direct C(sp2)H imidation has been developed. The reaction proceeds smoothly at 0 °C or ambient temperature to provide the desired products in good to excellent yields. The synthesis of 2‐alkyl‐ or 2‐alkyl‐fused benzimidazoles, which are generally inaccessible
Remarkable Effects of Axial π* Coordination on the Cr−Cr Quadruple Bond in Dichromium Paddlewheel Complexes
作者:F. Albert Cotton、Lee M. Daniels、Carlos A. Murillo、Isabel Pascual、Hong-Cai Zhou
DOI:10.1021/ja9912675
日期:1999.7.1
It is well-known that donation of electron density into the σ* orbital of a Cr−Cr quadruplebond causes major lengthening of the Cr−Cr distance, and there is some prior evidence that a similar lengthening is caused by dative interaction with the π* orbitals. Some molecules have now been made that allow a definitive assessment of this axial π* effect. A molecule has been designed to ensure that there