Hindered organoboron groups in organic chemistry. 25. The condensation of aliphatic aldehydes with dimesitylboryl stabilised carbanions to give alkenes.
作者:Andrew Pelter、Keith Smith、Said M.A. Elgendy
DOI:10.1016/s0040-4020(01)87983-7
日期:1993.8
In the presence of protic acids the condensation of aliphatic aldehydes with dimesitylboryl stabilised carbanions results in alkenes. In the presence of strong acids such as HCl or CF3SO3H, the products contain > 90% of E-alkenes in all cases tried. When acetic acid is used, then Z-alkenes may result predominantly, particularly in the cases of RsCHO and RtCHO. HX HCI, CF3SO3H gives E - alkenes in
在质子酸的存在下,脂族醛与二聚三苯甲基稳定的碳负离子的缩合会生成烯烃。在强酸(例如HCl或CF 3 SO 3 H)的存在下,在所有尝试的情况下,产品均含有> 90%的E-烯烃。当使用乙酸时,则可能主要产生Z-烯烃,特别是在R s CHO和R t CHO的情况下。在所有情况下,HXHCl,CF 3 SO 3 H均会生成E-烯烃。HXCH 3 CO 2 H,使得主要ž -烯烃当Rř秒,R叔。
Diastereoselective Free Radical Halogenation, Azidation, and Rearrangement of β-Silyl Barton Esters
作者:Douglas S. Masterson、Ned A. Porter
DOI:10.1021/ol0268182
日期:2002.11.1
[reaction: see text] Barton esters of beta-silylcarboxylic acids were decomposed by photolysis alone in organic solvents or in the presence of ethanesulfonyl azide or bromotrichloromethane. Products of the reaction, beta-silylthiopyridyl ethers, beta-silyl azides, or alkenes, were formed with significant control of stereochemistry.
Selective Photooxidation Reactions using Water-Soluble Anthraquinone Photocatalysts
作者:Wuyuan Zhang、Jenő Gacs、Isabel W. C. E. Arends、Frank Hollmann
DOI:10.1002/cctc.201700779
日期:2017.10.23
The aerobicorganocatalyticoxidation of alcohols was achieved by using water‐soluble sodium anthraquinone sulfonate. Under visible‐light activation, this catalyst mediated the aerobicoxidation of alcohols to aldehydes and ketones. The photo‐oxyfunctionalization of alkanes was also possible under these conditions.
A new and general method to functionalize the C(sp3)–C(sp2) bond of alkyl and alkene linkages has been developed, leading to the dealkenylative generation of carbon-centered radicals that can be intercepted to undergo Ni-catalyzed C(sp3)–C(sp2) cross-coupling. This one-pot protocol leverages the easily procured alkene feedstocks for organic synthesis with excellent functional group compatibility without
Preferential catalytic hydrogenation of aromatic compounds versus ketones with a palladium substituted polyoxometalate as pre-catalyst
作者:Vladimir Kogan、Zeev Aizenshtat、Ronny Neumann
DOI:10.1039/b110937p
日期:2002.3.11
finding that arenes could be selectively reduced in the presence of distal ketone groups under similar conditions, 30 bar H2 and 200°C. For example, 1-phenyl-2-propanone yielded 1-cyclohexyl-2-propanone with no reduction of the ketone moiety. Additionally, aromatic compounds with vicinal (conjugated) ketone moieties underwent complete hydrogenation to saturated hydrocarbons and catalytic McMurry coupling
一种 钯负载在γ-氧化铝或活性炭上的具有Keggin结构的取代多金属氧酸盐用作 催化剂 催化前体 氢化。催化剂系统快速启用氢化 的 竞技场在30 bar H 2和230 °C下。最有趣的是发现竞技场在30 bar H 2和200 °C的类似条件下,如果存在远端酮基,则可以选择性地还原H 2 O 3。例如,1-苯基-2-丙酮 屈服 1-环己基-2-丙酮 没有 减少酮部分的基团。此外,芳香族化合物与邻近 (结合)酮 部分完成 氢化 饱和 碳氢化合物 并观察到催化McMurry偶合 脂族醛。