Recent Advances in Silver‐Mediated Radical Difunctionalization of Alkenes

Abstract

Radical‐initiated difunctionalization of alkenes is one of the most important methods in organic synthesis and medicinal chemistry, which can be applied to synthesize value complex compounds as well as structural motifs that found in bioactive natural products and pharmaceuticals. In recent years, impressive progress have been made in this area with ideal silver catalysis. Here, we summarize recent advances in silver‐mediated radical difunctionalization of alkenes for the formation of diverse bonds, including 1) two‐component radical difunctionalization reactions enabled by an intramolecular cyclization process toward various cyclic compounds and 2) three‐component radical difunctionalization reactions leading to complex linear compounds. These silver‐mediated radical alkene difunctionalization transformations are general initiated by different radicals, such as carbon‐, oxygen‐, sulfur‐, phosphinyl‐, and halogen‐center radicals, followed by terminated with nucleophiles to form two new bonds in a single reaction.

Exploring the regioselectivity of the cyanoalkylation of 3-aza-1,5-dienes: photoinduced synthesis of 3-cyanoalkyl-4-pyrrolin-2-ones

“…Over the past decades, olefin functionalization has been proven to be a powerful technique to increase molecule complexity, and tremendous efforts have been directed toward it (Scheme 1a). 10–12 The dissociation energy of an alkenic π-bond is low, and the bond is generally broken upon the addition of an electrophile or a radical. On the other hand, enamides, a family of electron-rich alkenes with high conjugation energies and a class of useful building blocks for various biologically active compounds, are gaining increasing attention, and a diverse array of β-functionalized enamides could be furnished through β-C(sp 2 )–H bond functionalization (Scheme 1b).…”

Iron-Catalyzed Radical Annulation of Unsaturated Carboxylic Acids with Disulfides for the Synthesis of γ-Lactones

“…The direct difunctionalization of alkenes is a powerful tool in organic synthesis. − Specifically, the difunctionalization of unsaturated carboxylic acids has been the most straightforward and versatile synthetic method used for the preparation of substituted lactone derivatives via the functionalization of olefins, followed by intramolecular cyclization. − Generally, lactonization reactions involving unsaturated carboxyl acids can be divided into two types: (a) the nucleophilic addition of the carboxylic group to cationic or onium ion intermediates that result from the addition of strongly electrophilic reagents, such as halogen, selenium, or trifluoromethyl to the CC bond ,− and (b) lactonization that occurs via a radical single electron transfer (SET) or transition metal-assisted redox process. − To the best of our knowledge, the previously developed methods used for the construction of substituted γ-lactones are performed using thiols or thiophenols as the sulfurating reagents. , Although high reaction efficiencies are often observed in these reactions, the thiols or thiophenols involved in the reaction inevitably suffer from an undesirable odor. In addition, excess usage of sulfurating reagents may also cause a heavy burden on the environment.…”

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

“…It also provides a powerful tool for the construction of complex molecular frameworks [5][6][7]. A plethora of reviews involving transition metals such as Pd(II) [8][9][10], Ru(II) [11][12][13], Rh(III) [14][15][16], Mn(II) [17][18][19], Au(II/I) [20][21][22], Ag(I) [23][24][25] etc. in both cascade and sequential reactions have been published.…”