A Rh(III)-catalyzed tandem reaction for the synthesis of (quinazolin-2-yl)methanone derivatives has been explored from 2,1-benzisoxazoles and α-azido ketones. The transformation involves Rh(III)-catalyzed denitrogenation of α-azido ketones, aza-[4 + 2] cycloaddition, ring opening, and dehydration aromatization processes. Notably, the aza-[4 + 2] cycloaddition of an imine rhodium complex intermediate
Transition-Metal-Free One-Pot Tandem Synthesis of 3-Ketoisoquinolines from Aldehydes and Phenacyl Azides
作者:Budaganaboyina Prasad、Mandalaparthi Phanindrudu、Dharmendra Kumar Tiwari、Ahmed Kamal
DOI:10.1021/acs.joc.9b01534
日期:2019.10.4
An efficient and transition-metal-free strategy for the synthesis of 3-keto-isoquinolines in one pot has been developed from the easily accessible 2-(formylphenyl)acrylates and phenacyl azides. Various substituted aldehydes and phenacyl azides were successfully employed in this transformation to furnish a variety 3-keto-isoquinolines in very good yields. A number of controlled experiments were conducted
denitrogenation/oxidation reaction for the preparation of primary α-ketoamides was developed using α-azido ketones as a substrate and TEMPO as an oxidant. α-Azido ketones were denitrogenated in situ to form an imino ketone intermediate, which underwent a radical addition process and radical migration to form α-ketoamides. It is worth noting that the imino ketone intermediate is the key to this reaction.
以 α-叠氮基酮为底物,TEMPO 为氧化剂,开发了铜 (II) 促进的脱氮/氧化反应,用于制备初级 α-酮酰胺。α-叠氮基酮原位脱氮形成亚氨基酮中间体,其经过自由基加成过程和自由基迁移形成α-酮酰胺。值得注意的是,亚氨基酮中间体是该反应的关键。