Regioselective Photocatalytic Dialkylation/Cyclization Sequence of 3‐Aza‐1,5‐dienes: Access to 3,4‐Dialkylated 4‐Pyrrolin‐2‐ones

Abstract

A visible-light-induced regioselective tandem enamido β-C(sp 2 )À H alkylation/acrylamido alkylation/cyclizative alkenylation sequence of 3aza-1,5-dienes is presented. This protocol is regiospecific, features a broad substrate scope, and provides a direct access to 3,4-dialkylated 4pyrrolin-2-ones from readily available N-alkenylacrylamides. It is readily scalable to a gram scale, and could be induced by natural sunlight.

Photoinduced Tandem Cyanomethylation/Cyclization of Unsaturated Compounds: Access to Cyanomethylated 7- or 5-Membered N-Heterocycles

“…mp 169−170 °C. (8). A white solid after purification by flash column chromatography (petroleum ether/ethyl acetate = 5/1).…”

“…According to the above mechanistic studies and literature precedent, 7,8,[10][11][12][13]15 bromoacetonitrile and unsaturated trifluoroacetamide were performed as model compounds to describe the possible radical process (Scheme 4). First, the excited state of the photocatalyst was formed with the help of blue light, which was then oxidized by bromoacetonitrile to access Ir (IV) species and an α-cyano carbon-centered radical.…”

“…Among such, a variety of cascade cyanomethylation reactions to give CN-containing fused cycles has been finished by chemists, which also became the research hotspots. 7,8 Despite these critical achievements, to our best knowledge, some cyanomethylated medium cycles are still rarely studied, which are ongoing in our laboratory.…”

Photoinduced Regioselective Perfluoroalkylation/Cyclization Cascade of 3‐Aza‐1,5‐Dienes: Access to Pentasubstituted 3‐Perfluoroalkyl‐1,3‐Dihydropyrrol‐2‐Ones

“…However, we argue that the fundamental principle of polarity matching [21] might regulate the very regioselectivity in the reaction concerning a radical with proper electronic properties. In 2022, we explored the regioselectivity of the alkylation of 3‐aza‐1,5‐dienes under photocatalytic conditions, and the electron‐rich terminal enaminic double bond was preferentially alkylated in the dialkylation/cyclization sequence (Scheme 1e) [11d] . Although 3‐aza‐1,5‐dienes proved capable of undergoing radical cyclization to afford functionalized 1,3‐dihydropyrrol‐2‐ones, such reactions are rather limited and to date strictly restricted to sulfonylative or alkylative cyclization.…”

Catalytic asymmetric de novo construction of 4-pyrrolin-2-ones via intermolecular formal [3+2] cycloaddition of azoalkenes with azlactones

“…2 The combination of biological and synthetic importance has inspired chemists to explore new protocols to access such privileged scaffolds. In this context, racemic methodologies have been well developed, 3 while the catalytic asymmetric ones remain challenging and elusive. Direct functionalization of preprepared 4-pyrrolin-2-ones and intramolecular addition of tertiary enamides to ketones are the two known successful enantioselective approaches (Scheme 1b).…”