在这里,我们报告说,容易获得的基于甲硅烷基和硼的路易斯酸与手性铜催化剂结合能够克服未活化的烯酰胺(被称为反应性最低的羧酸衍生物)对有机镁试剂进行烷基化的反应性问题。在催化不对称共轭加成到烯酰胺中允许无与伦比的化学反应性和立体控制,该方法以其前所未有的反应范围而著称,即使是最具挑战性和合成上重要的甲基化也能以良好的产率和出色的对映选择性完成。该催化协议可耐受较宽的温度范围(-78 °C 至环境温度)和放大(10 g),而手性催化剂可以重复使用而不会影响整体效率。
decarbonylative alkenylation of aromatic carboxylic acids was developed. Under the reaction conditions, various benzoic acids including those bearing functional groups coupled to terminal alkenes, producing the corresponding internal alkenes in good to high yields. Cinnamic acids and bioactive benzoic acids such as 3-methylflavone-8-carboxylic acid, probenecid, adapalin, and febuxostat were also applicable to this
The invention relates to compounds of formula
wherein the substituents are as described in claim
1
. Compounds of formula I are modulators for amyloid beta and thus, they may be useful for the treatment or prevention of a disease associated with the deposition of β-amyloid in the brain, in particular Alzheimer's disease, and other diseases such as cerebral amyloid angiopathy, hereditary cerebral hemorrhage with amyloidosis, Dutch-type (HCHWA-D), multi-infarct dementia, dementia pugilistica and Down syndrome.
Copper-catalyzed synthesis of α,β-unsaturated acylamides via direct amidation from cinnamic acids and N-substituted formamides
作者:Hong Yan、Hailong Yang、Linhua Lu、Defu Liu、Guangwei Rong、Jincheng Mao
DOI:10.1016/j.tet.2013.06.078
日期:2013.9
A highly effective synthesis of α,β-unsaturated acylamides is reported for the first time via copper-catalyzed direct amidation between readily available cinnamic acids and N-substituted formamides. The protocol was easily accessible and practical.
solvents on the Heck coupling reaction of 4-trifluoromethyl-1-chlorobenzene (2) is presented. It is shown that a number of catalystsystems exist for efficient cross coupling of electron-deficient arylchlorides with various olefins. Basicity and steric demand of the ligand are two factors which determine the success of the reaction. In addition the phosphine/palladium ratio, the correct type and amount
Phosphites as Ligands for Efficient Catalysis of Heck Reactions
作者:Matthias Beller、Alexander Zapf
DOI:10.1055/s-1998-1760
日期:1998.7
The palladium-catalyzed Heck reaction of aryl halides in the presence of phosphite ligands is described for the first time. Aryl bromides and even electron deficient aryl chlorides can be coupled efficiently (turnover numbers up to 31 000) with different olefins using palladium/trialkyl- or triaryl phosphite mixtures as catalysts.