Regioselective Grafting of Two -CH2P(X)Ph2 Units (X = O, Lone Pair) onto a Resorcin[4]arene-Derived Cavitand
作者:Hani El Moll、David Sémeril、Dominique Matt、Loïc Toupet
DOI:10.1002/ejoc.200901201
日期:2010.2
first diphosphanes based on a resorcinarene-derived cavitand were obtained in six steps starting from 5,11,17,23-tetrabromo-4 (24),6( 10),12 ( 16),18(22)-tetramethylenedioxy-2,8,14,20-tetrapentylresorcin[4]arene. The synthesis of these bulky ligands was based on the selective C-2 functionalisation either of two proximal resorcinolic units or of two distal ones. The ligands, both of which were characterised
linked resorcinarenecavitands were synthesised. Their ability to bind transition-metal ions in a chelating fashion with the concomitant formation of capsular complexes was shown in their reactions with metal centres with two available binding sites. The solid-state structure of one of the complexes, a capsule with a partially embedded “trans-PtCl2” unit, was determined by single-crystal X-ray diffraction
合成了具有广泛分离的 P 中心和由两个共价连接的间苯二酚空腔组成的核心的两种二膦。它们以螯合方式结合过渡金属离子并伴随形成荚膜复合物的能力在它们与具有两个可用结合位点的金属中心的反应中显示出来。通过单晶 X 射线衍射确定其中一种复合物的固态结构,即具有部分嵌入的“反式 PtCL2”单元的胶囊。与 SnCL2 反应后,该配合物对苯乙烯的加氢甲酰化具有良好的活性。它对支链醛的活性和选择性明显优于参考复合物反式 PtCL2L2 所观察到的那些,其中 L 是单膦单腔配体。较高的活性可能反映了氢化中间体的初始形成,该中间体具有略微扭曲的三角双锥体结构,促进了囊内烯烃/PtH 插入步骤。观察到的醛选择性可能受胶囊形状的控制,与线性单元相比,胶囊在空间上更适合容纳支链 Pt-烷基单元。
Substrate-Selective Olefin Hydrogenation with a Cavitand-Based Bis(<i>N</i>
-anisyl iminophosphorane)
competitive hydrogenation of α-olefins (rhodium catalyst). A substrate-selectivity factor of 39.2 in favour of the linear olefin was observed after 1 h in the reduction of stoichiometric amounts of hex-1-ene and 3-ethyl-pent-1-ene. The catalyst was also shown to be suitable for the regioselective reduction of a compound that has two double bonds in different steric environments. The remarkable olefin discrimination