Room Temperature Coupling of Aryldiazoacetates with Boronic Acids Enhanced by Blue Light Irradiation
作者:Amanda F. Silva、Marco A. S. Afonso、Rodrigo A. Cormanich、Igor D. Jurberg
DOI:10.1002/chem.201905812
日期:2020.5.4
visible-light-promoted photochemical protocol is reported for the coupling of aryldiazoacetates with boronic acids. This photochemicalreaction shows great enhancement compared to the same protocol performed in the absence of light. Except for a few cases, the room temperature coupling in the dark (thermal process) generally does not work. When it does, it is likely to also involve free carbenes as key intermediates
Catalytic Enantio- and Diastereoselective Cyclopropanation of 2-Azadienes for the Synthesis of Aminocyclopropanes Bearing Quaternary Carbon Stereogenic Centers
作者:Xinxin Shao、Steven J. Malcolmson
DOI:10.1021/acs.orglett.9b02692
日期:2019.9.20
We report the catalyticenantio- and diastereoselective preparation of aminocyclopropanes by the cyclopropanation of terminal and (Z)-internal 2-azadienes with donor/acceptor carbenes derived from α-diazoesters. The resulting cyclopropanes bear quaternary carbon stereogenic centers vicinal to the amino-substituted carbon and are formed as a single diastereomer in up to 99:1 er and 97% yield with 0
我们报道了通过末端和( Z )-内部2-氮杂二烯与源自α-重氮酯的供体/受体卡宾的环丙烷化,催化对映和非对映选择性制备氨基环丙烷。所得环丙烷带有与氨基取代碳相邻的季碳立构中心,并以高达 99:1 er 和 97% 产率形成单一非对映异构体,其中使用 0.5 mol% 的 Rh 2 (DOSP) 4 和仅1.5当量的重氮试剂。内部氮杂二烯的转化提供了具有三个连续立体中心的环丙烷。
Catalytic asymmetric synthesis of 2,5-dihydrofurans using synergistic bifunctional Ag catalysis
作者:Taoda Shi、Shenghan Teng、Alavala Gopi Krishna Reddy、Xin Guo、Yueteng Zhang、Kohlson T. Moore、Thomas Buckley、Damian J. Mason、Wei Wang、Eli Chapman、Wenhao Hu
DOI:10.1039/c9ob01903k
日期:——
report a bifunctional Ag catalyst promotedintramolecular capture of oxonium ylides with alkynes for the enantioselectivesynthesis of 2,5-dihydrofurans. This represents unprecedented synergistic catalysis of a bifunctional Ag catalyst. Mechanistic studies revealed that [(R)-3,5-DM-BINAP](AgSbF6)2 (9) is likely to be the active catalytic species and that the reaction involves second order kinetics with
A mild synthetic protocol to access 2-ester pyrroles through Cu(OTf)2-catalysed carbene insertion/ester migration/cyclization of enaminones and α-diazo compounds is reported.
Copper‐Catalyzed Chemo‐ and Diastereoselective 1,3‐Dipolar Cycloaddition of Carbonyl Ylide and Aldehyde‐Tethered‐Cyclohexadienone to Access Polycyclic Systems
作者:Shiyong Peng、Hong Zhang、Yuqi Zhu、Ting Zhou、Jieyin He、Nuan Chen、Ming Lang、Hongguang Li、Jian Wang
DOI:10.1002/adsc.202100648
日期:2021.10.5
A copper-catalyzed tandem intermolecular ylide formation/intramolecular cycloaddition of diazo compounds and aldehyde-tethered-cyclohexadienones was reported, chemo- and diastereoselectively providing oxapolycyclic frameworks in moderate to excellent yields under mild conditions. This reaction creates two C−C bonds and one C−O bond with five stereocentres including two all-carbon quaternary centres