Access to chiral γ-butenolides via palladium-catalyzed asymmetric allylic C–H alkylation of 1,4-dienes
TL;DR: Asymmetric allylic C-H alkylation of 1,4-pentadienes with α-angelica lactones has been developed by tri-axial phosphoramidite-palladium catalysis as mentioned in this paper.
About: This article is published in Chemical Communications.The article was published on 2021-07-08. It has received 14 citations till now. The article focuses on the topics: Allylic rearrangement & Alkylation.
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TL;DR: In this article , diverse functionalizations of allylic C-H bonds of alkenes by thianthrenation have been demonstrated, featuring Z -selectivity to afford multi-alkyl substituted allylic esters, thioesters, ethers, amines, amides and arenes under metal-free conditions.
Abstract: Diverse functionalizations of allylic C–H bonds of alkenes by thianthrenation have been demonstrated, featuring Z -selectivity to afford multi-alkyl substituted allylic esters, thioesters, ethers, amines, amides and arenes under metal-free conditions.
26 citations
TL;DR: Chiral ligands bearing binaphthyl scaffolds have been proven to be versatile in asymmetric C-H functionalization due to their availability, unique stereochemical features, and ease of fine-tuning steric and electronic properties as mentioned in this paper .
Abstract: Over the past decades, transition metal-catalyzed enantioselective C–H functionalization has emerged as a straightforward and powerful tool for the rapid access to chiral molecules. The enormous advances achieved in this emerging area largely rely on the development of chiral ligands that can enable both high levels of enantiocontrol and efficiency. Chiral ligands bearing binaphthyl scaffolds have been proven to be versatile in asymmetric C–H functionalization due to their availability, unique stereochemical features, and ease of fine-tuning steric and electronic properties. In this Review, we summarized the advance in the applications of chiral ligands on the basis of the binaphthyl scaffold in asymmetric C–H functionalization.
12 citations
18 Nov 2022
TL;DR: In this article , an allylic C-H amination of 1,4-dienes has been achieved by palladium catalysis and linear dienyl allylic amines are the major products.
Abstract: Allylamines are important building blocks in the synthesis of bioactive compounds. The direct coupling of allylic C-H bonds and commonly available amines is a major synthetic challenge. An allylic C-H amination of 1,4-dienes has been accomplished by palladium catalysis. With aromatic amines, branch-selective allylic aminations are favored to generate thermodynamically unstable Z-allylamines. In addition, more basic aliphatic cyclic amines can also engage in the reaction, but linear dienyl allylic amines are the major products.
9 citations
TL;DR: In this article , a palladium-catalysed branch-selective and enanti-lective ally-H alkylation of α-alkenes is reported, which is capable of accommodating diverse types of αalkenes, ranging from feedstocks annually manufactured on a million-tonne scale to olefins tethering a wide scope of appended functionalities.
Abstract: Enantioselective functionalization of alkenes is an attractive and straightforward method to assemble molecular complexity from readily available chemical feedstocks. Although regio- and enantioselective transformations of the C=C bond of alkenes have been extensively studied, those of the allylic C–H bonds of unactivated alkenes are yet to be explored. Here we report a palladium-catalysed branch- and enantioselective allylic C–H alkylation that is capable of accommodating diverse types of α-alkenes, ranging from feedstocks annually manufactured on a million-tonne scale to olefins tethering a wide scope of appended functionalities, providing unconventional access to chiral γ,δ-unsaturated amides. Notably, mechanistic studies reveal that regioselectivity is not only governed by the coordination pattern of nucleophiles but also regulated by the ligational behaviours of ligands, highlighting the importance of the monoligation of chiral phosphoramidite ligands in provoking high levels of stereo- and branch-selectivity via a nucleophile coordination-enabled inner-sphere allylation pathway. The selective functionalization of C=C bonds of alkenes is well studied, however, regio- and enantioselective transformations of the allylic C–H bond of unactivated alkenes are relatively underexplored. Now, a palladium-catalysed branch-selective and enantioselective allylic C−H alkylation of α-alkenes is reported. The process tolerates a wide range of α-alkenes, from chemical feedstocks to bioactive α-alkenes
6 citations
TL;DR: An efficient Pd-catalyzed enantioselectiveγ-arylation of β, γ-unsaturated butenolides with aryl bromides with high ε-selectivity, good functional group tolerance and excellent enantiOSElectivity is reported.
Abstract: γ-Butenolide and γ-butyrolactone scaffolds are two types of important core structures in numerous natural products and bioactive targets. However, methods to construct the chiral quaternary arylated γ-butenolide are rarely explored. We herein report an efficient Pd-catalyzed enantioselective γ-arylation of β, γ-unsaturated butenolides with aryl bromides, which shows high γ-selectivity, good functional group tolerance and excellent enantioselectivity. Notably, this protocol also allows for facile construction of tricyclic tetrahydroindolines and tetrahydroisoquinolinones in one step. DFT calculations are consistent with the experimental results, suggesting that the γ-arylation is favoured than the α-arylation. Finally, this method is applied to the rapid synthesis of natural product ( R )-(+) - boivinianin A.
5 citations
References
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TL;DR: In this article, the representative (E)-1-alkenyldisiamylboranes and 1-alkenyl-1,3,2-benzodioxaboroles readily obtainable via hydroboration of 1 -alkynes react with (1) halides or (1)-alkynyl halides in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium and base to give corresponding conjugated (E-dienes or (E-)enynes with high regio-and
1,731 citations
TL;DR: Recent developments in asymmetric catalysis with phosphoramidites used as ligands are discussed, with a focus on the formation of carbon-carbon and carbon-heteroatom bonds.
Abstract: Asymmetric catalysis with transition-metal complexes is the basis for a vast array of stereoselective transformations and has changed the face of modern synthetic chemistry. Key to this success has been the design of chiral ligands to control the regio-, diastereo-, and enantioselectivity. Phosphoramidites have emerged as a highly versatile and readily accessible class of chiral ligands. Their modular structure enables the formation of ligand libraries and easy fine-tuning for a specific catalytic reaction. Phosphoramidites frequently show exceptional levels of stereocontrol, and their monodentate nature is essential in combinatorial catalysis, where a ligand-mixture approach is used. In this Review, recent developments in asymmetric catalysis with phosphoramidites used as ligands are discussed, with a focus on the formation of carbon-carbon and carbon-heteroatom bonds.
502 citations
TL;DR: This work has shown how the influence of a functional group may be relayed to a distant point in the molecule when these two sites are connected to by conjugated unsaturated linkages, such as double and triple bonds or aromatic moieties.
Abstract: Rephrasing Fuson's original formulation, the principle of
vinylogy explains how the influence of a functional group may be relayed to a distant point in the molecule when these two sites are connected to by conjugated unsaturated linkages, such as double and triple bonds or aromatic moieties.
This principle has been applied, over the years, to the majority of polar carbon-carbon bond-forming reactions of various repute, including the venerable Michael addition reaction, where the electrophilic -CdX site (1,2-addition) is “usurped” by a remote conjugated -RCdCR-CdX position (1,4-addition). The aldol addition reaction and the related
Mannich process, both fundamental pillars of organic synthesis, have not escaped this fate, and both of their
vinylogous extensions have emerged as extremely valuable
synthetic methodologies.
432 citations
TL;DR: Traditional approaches to alpha-methylene-Gamma-butyrolactones and alpha-alkylidene-gamma- butyrolActones are reviewed together with novel approaches, including those from the own research group, reported more recently.
Abstract: The amount of research activity concerning alpha-methylene-gamma-butyrolactones and alpha-alkylidene-gamma-butyrolactones has increased dramatically in recent years. This Review summarizes the structural types, biological activities, and biosynthesis of these compounds, concentrating on publications from the past 10 years. Traditional approaches to alpha-methylene-gamma-butyrolactones and alpha-alkylidene-gamma-butyrolactones are then reviewed together with novel approaches, including those from our own research group, reported more recently.
363 citations
TL;DR: Chiral multifunctional phosphine (R)-N-(2'-diphenylphosphanyl-[1,1']binaphthalenyl-2-yl)methanesulfonamide L3 is an efficient catalyst in the allylic substitutions of MBH acetates 1 with 2-trimethylsilyloxy furan 2 to provide gamma-butenolides 3 in good to excellent yields and enantiomeric excesses in the presence of water
Abstract: Chiral multifunctional phosphine (R)-N-(2′-diphenylphosphanyl-[1,1′]binaphthalenyl-2-yl)methanesulfonamide L2 or (R)-N-(2′-diphenylphosphanyl-[1,1′]binaphthalenyl-2-yl)acetamide L3 is an efficient catalyst in the allylic substitutions of MBH acetates 1 with 2-trimethylsilyloxy furan 2 to provide γ-butenolides 3 in good to excellent yields and enantiomeric excesses in the presence of water.
250 citations