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。
Electrochemical Oxidative Coupling Between Benzylic C(sp<sup>3</sup>)–H and N–H of Secondary Amines: Rapid Synthesis of α-Amino α-Aryl Esters
intermolecular electrochemical coupling between the benzylic C(sp3)–H bond and various secondary amines is reported. The electronic behavior of two electronically rich units viz the α-position of α-aryl acetates and amines was engineered electrochemically, thus facilitating their reactivity for the direct access of α-amino esters. A series of acyclic/cyclic secondary amines and α-aryl acetates were tested to furnish
under the Pd/C-catalyzed hydrogenation conditions in the presence of diethylamine and the method could also be applicable to the hydrodeoxygenation of morphine to afford 3-deoxy-7,8-dihydromorphine. Diethylamine is not only a scavenger of the corresponding methanesulfonic acid derivative, which is produced during the reaction progress, but also a strong promoter of the Pd/C-catalyzedreduction of aryl
A Pd/C-catalyzed deoxygenationmethod of phenolic hydroxyl groups via aryl triflates or mesylates using Mg metal in MeOH at room temperature was developed. The addition of NH4OAc dramatically affects the reactivity and reaction rate. This method is particularly attractive to provide an environmentally benign and widely applicable removal method of phenolic alcohols under quite mild reaction conditions
method for the deoxygenation of phenolic hydroxy groups via aryl triflates or mesylates has been established by using a combination of Pd/C-Mg-MeOH. The addition of NH(4)OAc to the system markedly accelerated the reaction rate and expanded the scope of the reaction. Mechanistic studies suggested that a single-electron transfer process from the Pd(0) center to the benzene ring is involved in the reduction