One-pot conversion of α-substituted arylacetaldehydes into α-dicarbonyl compounds
摘要:
Alpha-dicarbonyl compounds 7-12 can be easily prepared by reaction of methylene chloride solutions of several alpha-substituted arylacetaldehydes 1-6 with a slight excess of tris-(o,p-dibromophenyl) ammoniumyl hexachloro antimonate A.
APPARATUS AND METHOD FOR CARRYING OUT MULTIPLE REACTIONS
申请人:Bowden Ned
公开号:US20090299102A1
公开(公告)日:2009-12-03
The invention provides methods and an apparatus useful for site-isolating reagents or catalysts during chemical reactions. The methods and apparatus are useful for carrying out cascade or domino reactions.
A Materials Approach to Site-Isolation of Grubbs Catalysts from Incompatible Solvents and<i>m</i>-Chloroperoxybenzoic Acid
作者:Martin T. Mwangi、M. Brett Runge、Kevin M. Hoak、Michael D. Schulz、Ned B. Bowden
DOI:10.1002/chem.200800094
日期:2008.7.28
react by cross metathesis or ring-closing metathesis were added to the interior of the thimble and allowed to react. In the last step, m-chloroperoxybenzoicacid (MCPBA) dissolved in MeOH/H(2)O (1:1 v/v) was added to the exterior of the PDMS thimble. Small organic molecules diffused through the PDMS to react with MCPBA to form epoxides, but the Grubbs catalyst remained encapsulated. This result is important
描述了从MCPBA现场分离Grubbs第二代催化剂的方法的开发。在这些反应中,将Grubbs催化剂溶于由1-丁基-3-甲基咪唑六氟磷酸盐和二氯甲烷的混合物(1:1 v / v)组成的溶剂中,并完全封装在由聚二甲基硅氧烷(PDMS)制成的套管中。通过交叉复分解或闭环复分解反应的一系列分子被添加到套管的内部并使其反应。在最后一步中,将溶于MeOH / H(2)O(1:1 v / v)的间氯过氧苯甲酸(MCPBA)添加到PDMS顶针的外部。有机小分子通过PDMS扩散,与MCPBA反应形成环氧化物,但Grubbs催化剂仍被封装。该结果是重要的,因为Grubbs催化剂以MCPBA与Grubbs的比例为3000:1催化分解MCPBA。该两步级联序列的产率为67%至83%。该序列背后的概念是,小的有机分子通过PDMS具有较高的通量,而大分子(例如Grubbs催化剂)和离子试剂(例如MCPBA)具有通过P
<i>Cis</i>−<i>Trans</i> Isomerization and Oxidation of Radical Cations of Stilbene Derivatives
barrier to c-t unimolecularisomerization for c-3(*+)-5(*+) and 8(*+) than for c-1(*+), 2(*+), and 6(*+) due to the single bond character of the central C=C double bond for c-3(*+)-5(*+) and 8(*+) with a p-methoxyl group but not for c-1(*+), 2(*+), and 6(*+) without a p-methoxyl group because of the contribution of a quinoid-type structure induced by charge-spin separation. The isomerization proceeds via
The photochemistry of 2,3-bis(p-methoxyphenyl)oxirane: trapping of a C–C cleaved intermediate in an electron-transfer sensitised process
作者:Paul Clawson、Patricia M. Lunn、Donald A. Whiting
DOI:10.1039/c39840000134
日期:——
2,3-Bis(p-methoxyphenyl)oxirane (6) rearranges, with C–O cleavage, to the carbonyl compounds (8) and (9) on irradiation, direct or triplet sensitised, and thermally: in contrast C–C cleavage is observed with dicyanoanthracene as electron-transfersensitiser, and the resulting intermediate can be trapped by dipolarophiles in synthetically useful reactions.
Copper-catalyzed aerobic oxidative cleavage of C–C bonds in epoxides leading to aryl nitriles and aryl aldehydes
作者:Lijun Gu、Cheng Jin
DOI:10.1039/c5cc00360a
日期:——
Novel copper-catalyzedaerobic synthesis of aryl nitriles and aldehydes from epoxides via C-C single bond cleavage has been discovered. This reaction provides a practical method toward the synthesis of aryl nitriles and aldehydes, which are versatile intermediates and building blocks in organic synthesis.