Rhodium(III)‐Catalyzed Oxidative C(sp³)−H Alkenylation of 8‐Methylquinolines with Maleimides Under Aerobic Conditions

Abstract

A rhodium(III)‐catalyzed C(sp3)−H alkenylation of 8‐methylquinolines with electron‐deficient maleimides has been accomplished with the combination of copper acetate, 2,2,6,6‐tetramethylpiperidine‐1‐oxyl and oxygen as the oxidant. A variety of maleimides react with various 8‐methylquinolines to furnish the corresponding alkenylated products in moderate to good yields.

Rhodium‐Catalyzed C8‐Alkenylation of Isoquinolones with Maleimides

“…When benzyl‐protected maleimides ( 2 r – t ) were reacted with N ‐benzyl isoquinolone excellent selectivity for alkenylation was observed with good yields. Unprotected maleimides generally results in lower yield; [9c,d,e] however, the current methodology provided the corresponding alkenylated product ( 3 au ) in excellent yield with good selectivity. Diethyl maleate reacted sluggishly to give the corresponding alkenylated product ( 3 av ) in only 19 % yield.…”

Recent advances in transition-metal-catalyzed directed C–H alkenylation with maleimides

“…In 2020, Zhao developed a rhodium( iii )-catalyzed C(sp 3 )–H alkenylation of 8-methylquinolines with maleimides, furnishing the Heck-type products in moderate to good yields (Scheme 6). 23 In this catalytic system. The combination of Cu(OAc) 2 , 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and O 2 as the oxidant played a vital role in accomplishing this transformation.…”

Rh(III)-Catalyzed [4 + 1] Annulation of Sulfoximines with Maleimides: Access to Benzoisothiazole Spiropyrrolidinediones

“…Recently, maleimides have been efficiently used as π-unsaturates in the C–H functionalization reactions. − The resulting pyrrolidinedione skeleton is found in various natural products and pharmaceutically active compounds, and the pyrrolidinedione ring can be readily converted into biologically important organic molecules including pyrrolidines and γ-lactams . Mostly, maleimides underwent a Michael-type addition or Heck-type reaction with substituted aromatic compounds to deliver 3-aryl pyrrolidinediones or arylated maleimide derivatives. Maleimides were also known to undergo [3 + 2] and [4 + 2] annulation reactions.…”