Semihydrogenation of Alkynes Catalyzed by a Pyridone Borane Complex: Frustrated Lewis Pair Reactivity and Boron–Ligand Cooperation in Concert
作者:Felix Wech、Max Hasenbeck、Urs Gellrich
DOI:10.1002/chem.202001276
日期:2020.10.21
computations, reveal that the mode of action by which the boroxypyridine activates H2 is reminiscent of the reactivity of an intramolecular frustratedLewispair. However, it is the change in the coordination mode of the boroxypyridine upon H2 activation that allows the dissociation of the formed pyridone borane complex and subsequent hydroboration of an alkyne. This change in the coordination mode upon bond
报道了硼氧吡啶催化炔烃的无金属顺式选择性氢化。各种内部炔烃在80 bar于5 bar H 2下以良好的收率和立体选择性进行氢化。此外,本文所述的催化剂可实现末端炔烃的首次无金属半氢化反应。通过DFT计算证实的机制研究表明,硼氧基吡啶激活H 2的作用方式让人联想到分子内失意的Lewis对的反应性。但是,这是硼氧吡啶对H 2的配位模式的变化活化使得形成的吡啶酮硼烷配合物解离并随后炔烃的硼氢化。术语“硼配体配合”描述了键激活后配位模式的这种变化。
Carbonyl Imines from Oxaziridines: Generation and Cycloaddition of NOC Dipoles
作者:Katherine M. Partridge、Ilia A. Guzei、Tehshik P. Yoon
DOI:10.1002/anie.200905801
日期:2010.1.25
Dipoles apart: Unusual 1,3‐dipolar carbonylimines are generated in the presence of a bulky scandium(III) catalyst by undergoing a Lewis acid catalyzed rearrangement of N‐sulfonyl oxaziridines. The 1,3‐dipolar carbonylimines then undergo subsequent cycloaddition with a variety of dipolarophiles. tmbox=2,2′‐isopropylidenebis(4,4‐dimethyl‐2‐oxazoline).
Evidence that the availability of an allylic hydrogen governs the regioselectivity of the Wacker oxidation
作者:Matthew J. Gaunt、Jinquan Yu、Jonathan B. Spencer
DOI:10.1039/b103066n
日期:——
The allylic hydrogen is found to have a dramatic effect on the
regioselectivity of the Wacker oxidation, leading to the postulation that
an agostic hydrogen or enyl (σ + π) complex helps to stabilise the
key intermediate.
Conversion of (sp<sup>3</sup>)C–F Bonds of Alkyl Fluorides to (sp<sup>3</sup>)C–Heteroatom (Heteroatom = I, SR, SeR, TeR) Bonds by the Use of Magnesium Reagents Having Heteroatom Substituents
作者:Shameem Ara Begum、Jun Terao、Nobuaki Kambe
DOI:10.1246/cl.2007.196
日期:2007.1
A convenient method for conversion of (sp 3 )C-Fbonds to (sp 3 )C-Z (Z = I, SR, SeR, TeR) bonds has been developed. The reaction proceeds at room temperature using magnesium salts (Z-MgX). S N 2 mechanism for substitiution of primary alkyl fluorides with MgI 2 in ether was supported by the inversion of the stereochemistry of the carbon connecting to F.
已经开发了一种将 (sp 3 )CF 键转换为 (sp 3 )CZ (Z = I, SR, SeR, TeR) 键的简便方法。该反应在室温下使用镁盐 (Z-MgX) 进行。用 MgI 2 在醚中取代伯烷基氟化物的 SN 2 机制得到了连接到 F 的碳的立体化学反转的支持。
Monofunctional (Dimethylamino)silane as Silylating Agent
作者:Katalin Szabó、Ngoc Le Ha、Philippe Schneider、Peter Zeltner、Ervin sz. Kováts
DOI:10.1002/hlca.19840670813
日期:1984.12.19
The reaction of triorganyl(dimethylamino)silanes with surface-hydrated silicon dioxide has been studied. These silylatingagents are easy to prepare from the corresponding chloro or bromosilanes with dimethylamine. The resulting products are thermally stable and relatively volatile. Reaction with surface-hydrated silicon-dioxide preparations at 150–250°C for 170 h yields a dense grafted layer. However