scaffolds—ortho‐orientated terphenyls presenting twoatropisomeric Ar–Ar axes. These unusual structures were built up by using the C−Hactivation approach, and remarkably, both chiral axes were controlled with excellent stereoselectivity in a single transformation. During the reaction, not only does atroposelective functionalization of a biaryl precursor occur to establish one stereogenic axis, but an
Efficient and Practical Oxidative Bromination and Iodination of Arenes and Heteroarenes with DMSO and Hydrogen Halide: A Mild Protocol for Late-Stage Functionalization
efficient and practical system for inexpensive bromination and iodination of arenes as well as heteroarenes by using readily available dimethyl sulfoxide (DMSO) and HX (X = Br, I) reagents is reported. This mild oxidative system demonstrates a versatile protocol for the synthesis of aryl halides. HX (X = Br, I) are employed as halogenating reagents when combined with DMSO which participates in the present
Rapid Access to Azabicyclo[3.3.1]nonanes by a Tandem Diverted Tsuji–Trost Process
作者:Hannah G. Steeds、Jonathan P. Knowles、Wai L. Yu、Jeffery Richardson、Katie G. Cooper、Kevin I. Booker‐Milburn
DOI:10.1002/chem.202003762
日期:2020.11.11
system from simple pyrroles, employing a combined photochemical/palladium‐catalysed approach is reported. Substrate scope is broad, allowing the incorporation of a wide range of functionality relevant to medicinal chemistry. Mechanistic studies demonstrate that the process occurs by acid‐assisted C−N bond cleavage followed by β‐hydride elimination to form a reactive diene, demonstrating that efficient
A regioselective double Stille coupling reaction was explored using bicyclic stannolanes that were easily prepared from the radical cascade reaction of β-amino-α-methylene esters. Various 1-bromo-2-iodoarenes underwent the double coupling reaction to afford benzoisoindole derivatives in a regioselective manner, where the carbon attached to the iodine selectively coupled with the vinylic carbon, and
使用容易从β-氨基-α-亚甲基酯的自由基级联反应制备的双环锡烷来研究区域选择性双Stille偶联反应。各种1-溴-2-碘代芳烃进行双偶联反应,以区域选择性方式得到苯并异吲哚衍生物,其中连接至碘的碳与乙烯基碳选择性地偶联,然后连接至溴的碳与烷基碳选择性地偶联。分子内和分子间偶联反应的结合提供了六氢茚并[1,2- b]吡咯衍生物,收率高。在过量的CsF存在下,产率进一步提高。试图鉴定反应中间体,其中用盐酸和HBr水溶液分解锡烷基锡烷,得到三联双锥体(TBP)五配位锡配合物,如通过微观分析和119 Sn NMR证实的。使用DC1进行分解选择性地将氘引入到异亚甲基单元的E-位。在钯催化剂和DABCO的存在下,该配合物顺利进行分子内Stille偶联反应,得到六氢茚并[1,2- b]吡咯,收率高。这些结果表明,双偶联反应通过TBP锡配合物进行,从而促进了芳基卤化物与Csp 3-锡键之间的第二次分子内偶联反应。
Functionalized Photoreactive Compounds
申请人:Cherkaoui Mohammed Zoubair
公开号:US20080274304A1
公开(公告)日:2008-11-06
The present invention concerns functionalized photoreactive compounds of formula (I), that are particularly useful in materials for the alignment of liquid crystals. Due to the adjunction of an electron withdrawing group to specific molecular systems bearing an unsaturation directly attached to two unsaturated ring systems, exceptionally high photosensitivities, excellent alignment properties as well as good mechanical robustness could be achieved in materials comprising said functionalized photoreactive compounds of the invention.