Recent Advances in Transformations Involving Electron‐Rich Alkenes: Functionalization, Cyclization, and Cross‐Metathesis Reactions

Abstract

Due to the versatile reactivity and molecular complexity, as well as diversity, electron‐rich alkenes bearing nitrogen, oxygen, or sulfur atoms have been regarded as versatile reagents in organic synthesis. This review mainly focuses on the recent advances in the reaction development of electron‐rich alkenes since 2000, including mono‐/difunctionalization reactions, cyclization reactions, and cross‐metathesis reactions. Numerous protocols enabling facile and efficient transformations of electron‐rich alkenes to valuable compounds have been developed, which are discussed with special emphasis placed on the mechanistic aspects and the synthetic utilities. We hope that this review will help inspire future studies and promote developments in this area.

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

“…[14,15] A wide range of radical cyclization reactions using diverse alkene substrates has been developed to afford various carbo-/heterocycles, [16] while the direct βÀ C-(sp 2 )À H bond functionalization of enamides are attracting increasing attention. [17,18] Apparently, olefins, either electrondeficient or -rich, are both susceptible to radical addition owing to the fluffy nature of π-bonds, and thus a selectivity issue might arise in a radical-involved reaction of, say, a diene. [19,20] 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.…”

Stereoselective Palladium-Catalyzed Arylation of Exo-Glycals with Aryl Iodides

“…Palladium catalysis is one of the most versatile and useful tools for carrying out organic syntheses. Among basic types of palladium-catalyzed transformations, the Heck reaction and related chemistry occupy a special place. − Furthermore, the Heck reaction of electron-rich alkenes has been described and recently reviewed . Notably, a majority of the reported transformations afford α-substituted aryl vinyl ethers.…”

“…18−24 Furthermore, the Heck reaction of electron-rich alkenes has been described and recently reviewed. 25 Notably, a majority of the reported transformations afford α-substituted aryl vinyl ethers. Originally, the preparation of aryl-exo-glycals was demonstrated using palladium-catalyzed coupling of exo-glycals with organomercurates.…”

Dual Photoredox/Copper Catalyzed Fluoroalkylative Alkene Difunctionalization

“…Alkenes are a class of readily available starting materials for laboratory and industrial applications, and development of their transformations still attracts many research groups. Difunctionalization of an alkene constitutes a very efficient approach to access complex molecules from simple precursors. − For example, this can be realized by means of a two-component atom-transfer radical addition (ATRA) process, which is characterized by high atom economy. However, in terms of diversity-oriented synthesis, even more powerful would be three-component processes.…”