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。
Synthesis of Functionalized Silsesquioxane Nanomaterials by Rhodium‐Catalyzed Carbene Insertion into Si−H Bonds
作者:Jake R. Jagannathan、Karina Targos、Annaliese K. Franz
DOI:10.1002/anie.202110417
日期:2022.1.3
Carbene insertion into Si−Hbonds of silsesquioxane silanes was accomplished using RhII catalysis and diazo compounds as carbene precursors. Silsesquioxanes with up to eight Si−Hbonds were functionalized up to gram-scale. Diazo compounds with a fluorinated octyl group and BODIPY fluorophore were accessed to highlight the utility of diazo chemistry. Further transformations including a cross-coupling
Enantioselective Epoxypyrrolidines via a Tandem Cycloaddition/Autoxidation in Air and Mechanistic Studies
作者:Kaixiu Luo、Yongqiang Zhao、Jiawei Zhang、Jia He、Rong Huang、Shengjiao Yan、Jun Lin、Yi Jin
DOI:10.1021/acs.orglett.8b03605
日期:2019.1.18
A tandem cycloaddition/autoxidation reaction between heterocyclic ketene aminals and diazoester in air is described for the enantioselective preparation of epoxypyrrolidines. Notably, the results of mechanistic studies suggest that epoxide was oxidized from an sp3 C–C single bond, which is of mechanistic and practical interest as this protocol may be suitable for constructing other bioactive heterocyclic
Synthesis of 1,2,3,4,5,6,7-Heptasubstituted Cycloheptatrienes through Cycloaddition Reactions of Substituted Cyclopentadienones
作者:Dmitry N. Platonov、Aleksandr Yu. Belyy、Ivan V. Ananyev、Yury V. Tomilov
DOI:10.1002/ejoc.201600516
日期:2016.8
substituents in the ring are suggested. The first method is based on cycloaddition of 2,5-dimethoxycarbonyl-3,4-diphenylcyclopentadienone with substituted cyclopropenes and allows cycloheptatrienes containing two or three electron-withdrawing substituents in the molecule to be obtained. The second method employs a cascade reaction between a substituted cyclopentadienone and appropriate vinyldiazoacetates
Less reactive dipoles of diazodicarbonyl compounds in reaction with cycloaliphatic thioketones – First evidence for the 1,3-oxathiole–thiocarbonyl ylide interconversion
作者:Valerij A Nikolaev、Alexey V Ivanov、Ludmila L Rodina、Grzegorz Mlostoń
DOI:10.3762/bjoc.9.309
日期:——
compound was diazoacetylacetone. In the case of dimethyldiazomalonate competitive 1,3-electrocyclization yielded the corresponding thiirane at elevated temperature, which after spontaneous desulfurization produced a tetrasubstituted alkene. To explain the observed temperature dependence of the main reaction product type obtained from dimethyldiazomalonate and 2,2,4,4-tetramethyl-3-thioxocyclobutansmall