Combined Power of Organo‐ and Transition Metal Catalysis in Organic Synthesis

Abstract

The combination of organocatalysis with transition metal catalysis is an emerging research area for the scientific community. Various unprecedented transformations that are otherwise inaccessible by individual catalytic systems can be achieved with good efficiency and stereocontrolled manner by this dual-catalytic strategy. This Review presents a detailed discussion on the recent advances in dual catalytic systems combining organocatalysis and transition metal catalysis, covering the literature of the last five years. A wide variety of combinations of transition metals with organocatalysts including aminocatalysts, such as secondary amines and more recent primary amines, Brønsted acid catalysts, especially phosphoric acids based on the chiral BINOL scaffold and N-heterocyclic carbene catalysts, are discussed. Considering the great contribution of this domain to organic synthesis, the present and future potential of this new and exciting research field is highlighted.

Enantioselective cross-dehydrogenative coupling enabled by organocatalysis

“…[73][74][75][76][77][78][79][80][81][82][83][84][85] Particularly, in recent years, the combination of organocatalysis and transition metal catalysis or the synergy of organocatalysis and photocatalysis or electrocatalysis has been demonstrated as an efficient fashion to realize a series of enantio-selective CDC reactions, expanding the scope and potential of this field. [70][71][72][86][87][88][89][90][91][92][93][94][95][96][97][98] Two comprehensive reviews were published seven years ago on the topic of C-H functionalization through organocatalysis. 70,71 However, there is no reviews focusing on organocatalytic CDC reactions despite its significance.…”

“…73–85 Particularly, in recent years, the combination of organocatalysis and transition metal catalysis or the synergy of organocatalysis and photocatalysis or electrocatalysis has been demonstrated as an efficient fashion to realize a series of enantioselective CDC reactions, expanding the scope and potential of this field. 70–72,86–98…”

Catalytic Asymmetric α-Functionalization of α-Branched Aldehydes

“…While the enamine activation mode has proved quite successful for the enantioselective α-functionalization of linear aldehydes [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ], its extension to α-branched aldehydes progresses with paucity. In response to this situation, complementary activation modes have entered the field, including methods based on dual activation strategies [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. In 2014, Moreau and coworkers published a major review entitled asymmetric organocatalytic functionalization of α,α-disubstituted aldehydes through enamine activation [ 35 ].…”

Recent Advances in the Synthesis of 3,4-Dihydropyran-2-Ones Organocatalyzed by N-Heterocyclic Carbenes

“…Further, a rearrangement allows the formation of a homoenolate species III that, depending on the reaction conditions, is able to form either the azolium enolate species NHCs are easily produced in situ from the deprotonation of the corresponding azole (imidazolium and/or triazolium salts). Their versatility in modulating stereoelectronic properties through the modification of the backbone and N-substituents has generated considerable interest their role as catalysts in various types of reactions [9,10], either alone or coordinated to metals [24][25][26][27][28]. In the context of 3,4-dihydropyran-2-one synthesis, NHC catalysis involves [4+2]-and [3+3]-type cycloadditions, which, depending on the established reaction mechanisms, rely first on the in situ formation of the free NHC (I) with a subsequent nucleophilic attack to the corresponding substrate to yield the Breslow intermediate (II).…”