Cu‐Catalyzed Selective Oxy‐Cyanoalkylation of Allylamines with Cycloketone Oxime Esters and CO₂

Abstract

Summary of main observation and conclusionThe radical‐initiated carboxylative cyclization of allylamines with CO2 represents an efficient and highly promising strategy to afford valuable 2‐oxazolidinones. However, the radical precursors and pathways to generate radicals in such processes are still limited. Herein, we report the first Cu‐catalyzed selective oxy‐cyanoalkylation of allylamines with cycloketone oxime esters and CO2 via C—C bond cleavage. Many cyanoalkyl‐substituted 2‐oxazolidinones are obtained in moderate to good yields with high regio‐ and chemo‐selectivities. The utility of this redox‐neutral and cyanide‐free method is demonstrated with mild conditions, broad substrate scope, good functional group tolerance and easy scalability.

Visible Light-Driven Radical-Mediated C–C Bond Cleavage/Functionalization in Organic Synthesis

“…In 1975, Forrester and co-workers first disclosed a strategy for the formation of iminyl radicals based on the oxidation of oximino-acetic or oximino-propanoic acids . Later, the Zard group utilized oxidative cyclobutanone sulfenylimines or carboxymethyl oximes as iminyl radical precursors to promote selective C–C bond cleavage by using a stoichiometric radical initiator or UV irradiation. − Inspired by these pioneering reports, Selander, Shi, Guo, − Wang, and Li all reported metal (mostly copper and iron)-catalyzed C–C bond cleavages of oxime esters via SET processes. − These elegant studies inspired the development of novel catalytic methods for the formation of iminyl radicals under milder conditions.…”

Copper Mediated Chemo‐ and Stereoselective Cyanation Reactions

“…The desired 2‐oxazolidinones were obtained with high regio‐ and chemo‐selectivities and satisfactory yields with broad substrate scope (See Figure 99). [105] …”

Recent Developments in Radical Cross‐Coupling of Redox‐Active Cycloketone Oximes

“…Yu and co‐workers reported a copper‐catalyzed oxy‐cyanoalkylation of allylamines 28 with cycloketone oxime esters 27 under one atmosphere of CO 2 in MTBE ( tert ‐butyl methyl ether) (Scheme 10). [21] DBN (1,5‐diazabicyclo[4.3.0]non‐5‐ene) played a vital role in the transformation, as its omission led to a dramatically decrease in the yield of the product. This strategy provides an alternative choice to access cyanoalkylated 2‐oxazolidinones 29 .…”