Silica-Supported Dendrimer-Palladium Complex-Catalyzed Selective Hydrogenation of Dienes to Monoolefins
作者:Pumza P. Zweni、Howard Alper
DOI:10.1002/adsc.200505236
日期:2006.4
The selective hydrogenation of cyclic and acyclicdienes to monoolefins occurs under very mild conditions, in the presence of silica-supported PAMAM-Pd complexes. The activity and selectivity of this reaction is sensitive to the dendrimer structure. These dendritic complexes display excellent recycle properties, retaining activity for up to eight recycles.
Epoxidation of alkenes by dimethyldioxirane: Evidence for a spiro transition state
作者:A.L Baumstark、C.J McCloskey
DOI:10.1016/s0040-4039(00)95499-6
日期:1987.1
The relative reactivity series for the epoxidation of alkenes by dimethyldioxirane showed the reaction to be unexpectedly sensitive to steric factors; compounds were ∼8 times as reactive as the isomers.
High Yield of Liquid Range Olefins Obtained by Converting <i>i</i>-Propanol over Zeolite H-ZSM-5
作者:Uffe V. Mentzel、Saravanamurugan Shunmugavel、Sarah L. Hruby、Claus H. Christensen、Martin S. Holm
DOI:10.1021/ja907692t
日期:2009.11.25
Methanol, ethanol, and i-propanol were converted under methanol-to-gasoline (MTH)-like conditions (400 degrees C, 1-20 bar) over zeolite H-ZSM-5. For methanol and ethanol, the catalyst lifetimes and conversion capacities are comparable, but when i-propanol is used as the reactant, the catalyst lifetime is increased dramatically. In fact, the total conversion capacity (calculated as the total amount
A crystalline, internally-coordinated chloroborane for asymmetric hydroboration
作者:Breanna von Dollen、John L. Wood、Quentin R. Savage、Andrew J. Jones、Charles M. Garner
DOI:10.1016/j.tet.2022.132654
日期:2022.2
Asymmetric hydroboration is an important method in the preparation of enantiomerically-enriched compounds that are necessary in many areas of chemistry. Here is reported the preparation of a unique chiral chloroborane-internal ether complex and its applications in asymmetric hydroboration. This chloroborane is easily obtained in crystalline, solvent-free and enantiomerically pure form. The chemical
不对称硼氢化是制备对映体富集化合物的重要方法,在许多化学领域都是必需的。本文报道了一种独特的手性氯硼烷-内醚配合物的制备及其在不对称硼氢化中的应用。这种氯硼烷很容易以结晶、无溶剂和对映体纯的形式获得。路易斯碱性甲氧基的化学位移对硼环境敏感,这使得该试剂特别适用于核磁共振研究,其中非对映异构体比例在许多情况下可以在氧化之前确定,甚至动力学也相对容易进行。它很容易与前手性烯烃反应,氧化后产生高达 82% ee 的醇。二烷基氯硼烷中间体可以通过直接重结晶或作为空气稳定的乙醇胺络合物进行非对映体纯化,氧化后得到高达 99.8% ee 的醇。氯基很容易被氢化物取代原位,允许分子内不对称硼氢化和氘硼化,具有分子间硼氢化不能提供的高度区域化学控制。
Polylithiumorganic compounds - 20.
作者:Adalbert Maercker、Ulrich Girreser
DOI:10.1016/s0040-4020(01)85287-x
日期:1994.1
The reaction of various cyclic and acyclic alkynes with lithium dust (2% sodium) to form vicinal dilithioalkenes has been investigated: Aliphatic alkynes, e.g. 3-hexyne (27a), exclusively afford the corresponding (E)-dilithioalkenes, insoluble solids which are stable at room temperature and allow access to a variety of tetrasubstituted olefins in acceptable yields