Transition-Metal-Catalyzed Asymmetric Allylation of Carbonyl Compounds with Unsaturated Hydrocarbons

Synthesis ◽  
2017 ◽  
Vol 50 (05) ◽  
pp. 956-967 ◽  
Author(s):  
Liu-Zhu Gong ◽  
Pu-Sheng Wang ◽  
Meng-Lan Shen

The asymmetric allylation of carbonyl compounds is an important process for the formation of carbon–carbon bonds, generating optically active homoallylic alcohols that are versatile building blocks with widespread applications in organic synthesis. The use of readily available unsaturated hydrocarbons as allylating reagents in the transition-metal-catalyzed asymmetric allylation has received increasing interest as either a step- or an atom-economy alternative. This review summarizes transition-metal-catalyzed enantioselective allylations on the basis of the ‘indirect’ and ‘direct’ use of simple unsaturated hydrocarbons (include dienes, allenes, alkynes, and alkenes) as allylating reagents, with emphasis on highlighting conceptually novel reactions.1 Introduction2 ‘Indirect’ Use of Unsaturated Hydrocarbons in Asymmetric Allylation of Carbonyl Compounds2.1 Enantioselective Allylation with 1,3-Dienes2.2 Enantioselective Allylation with Allenes2.3 Enantioselective Allylation with Alkenes3 ‘Direct’ Use of Unsaturated Hydrocarbons in Asymmetric Allylation of Carbonyl Compounds3.1 Enantioselective Allylation with 1,3-Dienes3.2 Enantioselective Allylation with Allenes3.3 Enantioselective Allylation with Alkynes3.4 Enantioselective Allylation with Alkenes4 Conclusions

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1173
Author(s):  
Roberto Sala ◽  
Camilla Loro ◽  
Francesca Foschi ◽  
Gianluigi Broggini

A wide range of methodologies for the preparation of organic azides has been reported in the literature for many decades, due to their interest as building blocks for different transformations and their applications in biology as well as in materials science. More recently, with the spread of the use of transition metal-catalyzed reactions, new perspectives have also materialized in azidation processes, especially concerning the azidation of C–H bonds and direct difunctionalization of multiple carbon-carbon bonds. In this review, special emphasis will be placed on reactions involving substrates bearing a leaving group, hydroazidation reactions and azidation reactions that proceed with the formation of more than one bond. Further reactions for the preparation of allyl and vinyl azides as well as for azidations involving the opening of a ring complete the classification of the material.


Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 861 ◽  
Author(s):  
Ha-Eun Lee ◽  
Dopil Kim ◽  
Ahrom You ◽  
Myung Hwan Park ◽  
Min Kim ◽  
...  

α-Functionalization of carbonyl compounds in organic synthesis has traditionally been accomplished via classical enolate chemistry. As α-functionalized carbonyl moieties are ubiquitous in biologically and pharmaceutically valuable molecules, catalytic α-alkylations have been extensively studied, yielding a plethora of practical and efficient methodologies. Moreover, stereoselective carbon–carbon bond formation at the α-position of achiral carbonyl compounds has been achieved by using various transition metal–chiral ligand complexes. This review describes recent advances—in the last 20 years and especially focusing on the last 10 years—in transition metal-catalyzed α-alkylations of carbonyl compounds, such as aldehydes, ketones, imines, esters, and amides and in efficient carbon–carbon bond formations. Active catalytic species and ligand design are discussed, and mechanistic insights are presented. In addition, recently developed photo-redox catalytic systems for α-alkylations are described as a versatile synthetic tool for the synthesis of chiral carbonyl-bearing molecules.


Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 391 ◽  
Author(s):  
Ke Cao ◽  
Cai-Yan Zhang ◽  
Tao-Tao Xu ◽  
Ji Wu ◽  
Xin-Yu Wen ◽  
...  

Aromatic heterocycles are ubiquitous building blocks in bioactive natural products, pharmaceutical and agrochemical industries. Accordingly, the carborane-fused heterocycles would be potential candidates in drug discovery, nanomaterials, metallacarboranes, as well as photoluminescent materials. In recent years, the transition metal catalyzed B-H activation has been proved to be an effective protocol for selective functionalization of B-H bond of o-carboranes, which has been further extended for the synthesis of polyhedral borane cluster-fused heterocycles via cascade B-H functionalization/annulation process. This article summarizes the recent progress in construction of polyhedral borane cluster-fused heterocycles via B-H activation.


2020 ◽  
Vol 18 (3) ◽  
pp. 391-399 ◽  
Author(s):  
Hongru Zhang ◽  
Xin Su ◽  
Kaiwu Dong

Hydrocyanation is a powerful method for the preparation of nitriles which are versatile building blocks for the synthesis of amines, acids and amides.


Synlett ◽  
2021 ◽  
Author(s):  
Margarita Escudero-Casao ◽  
Giulia Licini ◽  
Manuel Orlandi

The transition metal catalyzed α-arylation of carbonyl compounds was first reported by Buchwald and Hartwig in 1997. This transformation has been used and studied extensively over the last two decades. Enantioselective variants were also developed that allow for controlling the product stereochemistry. However, these suffer several limitations in the context of formation of tertiary stereocenters. Presented here is our group’s contribution to this research area. The chiral Cu-bis(phosphine) dioxides catalytic system that we reported allowed accessing the enantioselective α-arylation of ketones that were not suitable for this transformation before in good yields and er up to 97.5:2.5. Preliminary insight and speculation concerning the reaction mechanism involving the unusual pairing of bis(phosphine) dioxides with transition metal catalysts is also given.


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