Preparation, characterization and use of 1,3-disulfonic acid imidazolium hydrogen sulfate as an efficient, halogen-free and reusable ionic liquid catalyst for the trimethylsilyl protection of hydroxyl groups and deprotection of the obtained trimethylsilanes
摘要:
Novel 1,3-disulfonic acid imidazolium hydrogen sulfate, a halogen-free ionic liquid, is a recyclable and eco-benign catalyst for the trimethylsilyl protection of hydroxyl groups at room temperature under solvent free conditions to afford trimethylsilanes in excellent yields (92-100%) and in very short reaction times (1-5 min). Deprotection of the resulting trimethylsilanes can also be achieved using the same catalyst in methanol. The catalyst was characterized by IR. H-1 NMR, C-13 NMR and MS studies. All the products were extensively characterized by IR, H-1 NMR, MS, and elemental and melting point analyses. This new method consistently has the advantages of excellent yields and short reaction times. Further, the catalyst can be recovered and reused for several times without loss of activity. The work-up of the reaction consists of a simple separation, followed by concentration of the crude product and purification. (C) 2012 Elsevier B.V. All rights reserved.
Turning the Nitrogen Atoms of an Ar<sub>2</sub>
P−CH<sub>2</sub>
−N−N−CH<sub>2</sub>
−PAr<sub>2</sub>
Motif into Uniquely Configured Stereocenters: A Novel Diphosphane Design for Asymmetric Catalysis
作者:Eva Diehl née Knobloch、Reinhard Brückner
DOI:10.1002/chem.201706160
日期:2018.3.7
Hexahydropyridazines with CH2PAr2 groups at both N atoms are newly designed 1,4‐diphosphanes and were synthesized for the first time. Their N atoms assume a single configuration under the influence of stereocenters at C‐5 and C‐6. In the solid state, these N‐atoms bind the CH2PAr2 substituents axially. Combined with Pd0, N,N′‐chiral diphosphanes of this kind catalyzed Tsuji–Trost type allylations of dialkyl malonates
在两个N原子上均具有CH 2 PAr 2基团的六氢哒嗪是新设计的1,4-二膦烷,是首次合成。它们的N原子在C-5和C-6的立体中心的影响下呈单一构型。在固态下,这些N原子轴向结合CH 2 PAr 2取代基。与此类的Pd 0,N,N'-手性二膦烷结合,可有效地与乙酸外消旋1,3-二苯基烯丙基乙酸酯催化二甲基丙二酸酯的Tsuji-Trost型烯丙基化,且ee高达91% 。
New methods of synthesis of boron, germanium, and tin derivatives of pentavalent phosphorus thioacids
作者:Il'yas S. Nizamov、Tat'yana P. Sorokina、Il'nar D. Nizamov、Nailya G. Galimullina、Elvira S. Batyeva、Vladimir A. Alfonsov
Synthesis of C-silylated products by silylation of various functional saturated derivatives (aldehydes, nitriles, acid anhydrides and esters), by mens of the Me3SiClLiTHF system used at 0–10°C, is described. Most of the products obtained are new. A mechanism explaining the formation of these derivatives is proposed.
描述了通过在0–10°C下使用Me 3 SiCl 3 Li 3 THF体系对各种功能性饱和衍生物(醛,腈,酸酐和酯)进行甲硅烷基化来合成C-硅烷化产物的方法。获得的大多数产品都是新产品。提出了解释这些衍生物形成的机理。
Stable monoalkoxyfluorophosphoranes
作者:Dominique U. Robert、Gilles N. Flatau、Claire Demay、Jean G. Riess
DOI:10.1039/c3972001127b
日期:——
Thermally stablemonoalkoxyfluorophosphoranes, R1PF3(OR2), with R1= Me and Ph, are obtained when R2 is either an electron-attractive group or a neopentyl group; the fluorophosphoranes undergo slow redistribution reactions of fluorine vs. alkoxy-groups in which the five-co-ordinate state of the phosphorous atom is preserved.
Silica Sulfate, an Efficient Catalyst for the Trimethylsilylation of Alcohols
作者:Tong‐Shou Jin、Ruo‐Fei Tian、Li‐Bin Liu、Ying Zhao、Tong‐Shuang Li
DOI:10.1080/00397910600602495
日期:2006.7
An easy method for the preparation of trimethylsilyl ethers from alcohols and 1,1,1,3,3,3-hexamethyl-disilazane (HMDS) using silica sulfate as a catalyst under mild conditions in excellent yields is described.