A novel ruthenium-catalyzed cyclization of ketoxime carboxylates with N,N-dimethylformamide (DMF) for the synthesis of tetrasubstituted symmetrical pyridines has been developed. A methyl carbon on DMF performed as a source of a one carbon synthon. And NaHSO3 plays a role in the reaction.
Synthesis of Fused-Pyrazines <i>via</i>
Palladium-Catalyzed Double Benzyl Isocyanide Insertion and Cross-Dehydrogenative Coupling
作者:Gopal Chandru Senadi、Bing-Chun Guo、Yu-Ching Chang、Wan-Ping Hu、Jeh-Jeng Wang
DOI:10.1002/adsc.201701202
日期:2018.2.1
palladium‐catalyzed cascade reaction has been realized for the synthesis of 5H‐pyrrolo[2,3‐b]pyrazines and 5H‐pyrazino[2,3‐b]indoles from benzyl isocyanide by choosing o‐pivaloyloximes or o‐iodoanilines as a suitable substrate. The key steps involved are (i) oxidative addition of palladium through N–O or C–I cleavage; (ii) migratory double isocyanide insertion; and (iii) cross‐dehydrogenativecoupling. Notable
通过选择邻-吡咯并酮肟或邻-碘苯胺,已实现了钯催化的级联反应,可从异氰酸苄酯合成5 H-吡咯并[2,3- b ]吡嗪和5 H-吡嗪并[2,3- b ]吲哚。作为合适的基材。涉及的关键步骤是(i)通过N-O或C-I裂解氧化钯的加成;(ii)迁移性双异氰酸酯插入;(iii)交叉脱氢偶联。显着的特征是良好的官能团耐受性以及三个C–C和一个C–N键的形成。
Base-Promoted [3+2]-Annulation of Oxime Esters and Aldehydes for Rapid Isoxazoline Formation
作者:Huawen Huang、Feifei Li、Zhenhua Xu、Jinhui Cai、Xiaochen Ji、Guo-Jun Deng
DOI:10.1002/adsc.201700730
日期:2017.9.18
A base‐promoted [3+2]‐annulation of ketoxime esters and aldehydes is disclosed for the facile and rapid synthesis of 3,5‐disubstituted and 3,4,5‐trisubstituted isoxazolines. The key to our success is the pivalate leaving group of the oxime substrates, combined with cesium carbonate as promoter. This chemistry allows the assembly of a vast array of isoxazoline derivatives under simple base conditions
synthesis of alkynylated isoquinolines and biisoquinolines from various aryl ketone O-pivaloyloxime derivatives and 1,3-diynes via rhodium-catalyzed C–H bond activation. In this transformations, alkynylated isoquinolines, 3,4′- and 3,3′-biisoquinolines could be obtained respectively through changing the reaction conditions. Mechanistic investigation revealed that the C–H activation of aryl ketone O-pivaloyloxime