优化了光学富集的脱氢哌啶基硼酸酯与碳酸肉桂酯的钯催化交叉偶联,以最大限度地减少立体化学侵蚀。尽管两个不对称烯丙基片段的偶联可能产生四种可能的区域异构体,但使用 ( p -CF 3 C 6 H 4 ) 3 P 作为配体的最佳程序仅提供线性 2-烯丙基化 3,4-脱氢哌啶 (>98:2 rr ) 对映体特异性高达 99%。
Enantioselective Syntheses of
<i>Strychnos</i>
and
<i>Chelidonium</i>
Alkaloids through Regio‐ and Stereocontrolled Cooperative Catalysis
作者:Luke S. Hutchings‐Goetz、Chao Yang、James W. B. Fyfe、Thomas N. Snaddon
DOI:10.1002/anie.202005151
日期:2020.9.28
We describe enantioselective syntheses of strychnos and chelidonium alkaloids. In the first case, indole acetic acid esters were established as excellent partner nucleophiles for enantioselective cooperative isothiourea/Pd catalyzed α‐alkylation. This provides products containing indole‐bearing stereocenters in high yield and with excellent levels of enantioinduction in a manner that is notably independent
Direct Palladium-Catalyzed Intermolecular Allylation of Highly Electron-Deficient Polyfluoroarenes
作者:Shilu Fan、Fei Chen、Xingang Zhang
DOI:10.1002/anie.201008174
日期:2011.6.20
A simple operation: The use of readily available PPh3, high reaction efficiency, and good stereo‐ and regioselectivity provided useful and operationally simple access to polyfluoroarylated derivatives through the title transformation (see scheme; phen=1,10‐phenanthroline). The reaction mechanism was also studied.
Synthesis of β<sup>3</sup>-Amino Esters by Iridium-Catalyzed Asymmetric Allylic Alkylation Reaction
作者:Chao-Guo Cao、Bin He、Zhengyan Fu、Dawen Niu
DOI:10.1021/acs.oprd.9b00280
日期:2019.8.16
A method to prepare chiral β3-amino esters from methyl 3-aminopropanoate was described. This method capitalized on a sequence involving an Ir-catalyzed asymmetric allylation of 2-azaallyl anions and a 2-aza-Cope rearrangement. β3-Amino esters containing a versatile alkene group were prepared.
A Regio‐ and Stereodivergent Synthesis of Homoallylic Amines by a One‐Pot Cooperative‐Catalysis‐Based Allylic Alkylation/Hofmann Rearrangement Strategy
作者:Colin M. Pearson、James W. B. Fyfe、Thomas N. Snaddon
DOI:10.1002/anie.201905426
日期:2019.7.29
Herein, we report a modular synthetic route to linear and branched homoallylic amines that operates through a sequential one-pot Lewis base/transition-metal catalyzed allylic alkylation/Hofmann rearrangement strategy. This protocol is operationally trivial, proceeds from simple and easily prepared substrates and catalysts, and enables all aspects of regio- and stereoselectivity to be controlled through
The Pd-catalyzed cross-coupling of allylic carbonates and allyIB(pin) is described. The regioselectivity of this reaction is sensitive to the bite angle of the ligand, with small-bite-angle ligands favoring the branched substitution product. This mode of regioselection is consistent with a reaction that operates by a 3,3' reductive elimination reaction. In the presence of appropriate chiral ligands, this reaction is rendered enantioselective and applies to both aromatic and aliphatic allylic carbonates.