Recent Progress in Transition Metal‐Catalyzed Regioselective Functionalization of Unactivated Alkenes/Alkynes Assisted by Bidentate Directing Groups

Abstract

The catalytic functionalization of alkenes is among the most important and powerful methods for construction of two new bonds through cleavage of the π bonds, which is widely used for construction of numerous complex organic molecules. Recently, the strategy that involves directing groups-assisted regioselective functionalization of alkenes has found great synthetic application value, and great achievements have been made in the functionalization of unactivated alkenes and alkynes. This Minireview summarizes the recent progress in transition metal-catalyzed functionalization of unactivated alkenes and alkynes assisted by bidentate directing groups with high chemo-, regio-, and stereo-selectivity.[a] Dr. Scheme 1. Sequential carbopalladation of cyclooctadiene with a stoichiometric amount of PdCl 2 . Reproduced with permission from Ref. 8 a. . Regioselective carbopalladation of allylic amines with stoichiometric amount of Li 2 PdCl 4 . Reproduced with permission from Ref. 8 b. . Proposed mechanism of Ni(0)-catalyzed AQ-directed intermolecular 1,2-dicarbofunctionalization. Reproduced with permission from Ref. 22. Scheme 15. Ni-catalyzed three-component 1,2-dialkylation of unactivated alkenes. Reproduced with permission from Ref. 23. Scheme 16. Proposed mechanism of Ni-catalyzed three-component 1,2dialkylation of unactivated alkenes. Reproduced with permission from Ref. 23. Scheme 17. Pd(II)-catalyzed regioselective syn-hydroarylation of unactivated alkynes. Reproduced with permission from Ref. 26.

Nickel‐CatalyzedDicarbofunctionalization of Alkenes†

“…[ 1‐7 ] Among the developed methods, transition metal‐catalyzed difunctionalization of alkenes enables preparation of complex molecules from simple available alkenes by diversifying the C=C double bond with high atom‐ and step‐economic efficiency. [ 8‐21 ] In particular, the dicarbofunctionalization of alkenes has gained special attention because it can construct complex carbon skeletons by assembling two carbon entities across the C=C bond and forming two C—C bonds in an one‐pot reaction (Scheme 1). [ 22‐25 ] Over the past decade, considerable efforts have been devoted to this area and impressive progress has been achieved.…”

Directed Copper-Catalyzed Intermolecular Aminative Difunctionalization of Unactivated Alkenes

“…Herein, we report a directed copper-catalyzed intermolecular aminative difunctionalization of unactivated alkenes with dialkylamino source (Figure D) . The tethered directing group played two key roles for the transformation: (1) coordinating with the transition metal to force the aminyl radical-metal complex close to the olefin moiety, which would greatly promote the subsequent migratory insertion, and (2) serving as a bidentate ligand to stabilize the plausible high-valent copper intermediate, allowing for either reductive elimination or ligand exchange followed by reductive elimination.…”

Copper-Catalyzed Diamination of Unactivated Alkenes With Electron-Rich Amino Sources

“…This result, together with the cis -configuration of diamines 4 , lift the veil on the reaction mechanism. After an SET process between complex A and 4-bromomorpholine, the formed Cu­(II) intermediate B could undergo a reaction sequence as proposed in our previous work, which involves nitrogen radical addition to an olefin, the formation of a Cu­(III) complex via a recombination of the resultant carbon radical and Cu­(II), and reductive elimination to deliver the vicinal bromoamine C . The subsequent S N 2 substitution reaction of the bromo atom by an adjacent N-atom formed the aziridinium intermediate D , which could undergo ring-opening with an external alkylamine to give the cis -product (Scheme , path a).…”