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1.
Asymmetric Cascade Reaction to Allylic Sulfonamides from Allylic Alcohols by Palladium(II)/Base‐Catalyzed Rearrangement of Allylic Carbamates
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Dipl.‐Chem. Johannes Moritz Bauer Dr. Wolfgang Frey Prof. Dr. René Peters 《Angewandte Chemie (International ed. in English)》2014,53(29):7634-7638
A regio‐ and enantioselective tandem reaction is reported capable of directly transforming readily accessible achiral allylic alcohols into chiral sulfonyl‐protected allylic amines. The reaction is catalyzed by the cooperative action of a chiral ferrocene palladacycle and a tertiary amine base and combines high step‐economy with operational simplicity (e.g. no need for inert‐gas atmosphere or catalyst activation). Mechanistic studies support a PdII‐catalyzed [3,3] rearrangement of allylic carbamates—generated in situ from the allylic alcohol and an isocyanate—as the key step, which is followed by a decarboxylation. 相似文献
2.
Iridium‐Catalyzed Regio‐ and Enantioselective Allylic Substitution of Trisubstituted Allylic Electrophiles
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Ming Chen Prof. John F. Hartwig 《Angewandte Chemie (International ed. in English)》2016,55(38):11651-11655
The first Ir‐catalyzed enantioselective allylation of trisubstituted allylic electrophiles has been developed. Through modification of the leaving group of allylic electrophiles, we found that trisubstituted allylic phosphates are suitable electrophiles for asymmetric allylation. The reaction of allylic phosphates with enol silanes derived from dioxinones gave allylated products in good yields with high enantioselectivities. 相似文献
3.
Enantioselective Synthesis of Tertiary Allylic Fluorides by Iridium‐Catalyzed Allylic Fluoroalkylation
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Trevor W. Butcher Prof. John F. Hartwig 《Angewandte Chemie (International ed. in English)》2018,57(40):13125-13129
Few allylic electrophiles containing two different substituents at a single allyl terminus and none in which one of the two substituents is a heteroatom, have been shown previously to react with iridium catalysts to form substitution products. We report that iridium‐catalysts are uniquely suited to form tertiary allylic fluorides enantioselectively by the addition of a diverse range of carbon‐centered nucleophiles at the fluorine‐containing terminus of 3‐fluoro‐substituted allylic esters. The products contain tertiary stereogenic centers bearing a single fluorine, which are isosteric with common tertiary stereocenters containing a single hydrogen. Computational studies reveal the principal steric interactions influencing the stability of endo and exo π‐allyl intermediates formed from 3,3‐disubstituted allylic electrophiles. 相似文献
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5.
One‐Pot Synthesis of Allylic Sulfones,Ketosulfones, and Triflyl Allylic Alcohols from Domino Reactions of Allylic Alcohols with Sulfinic Acid under Metal‐Free Conditions
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Xue‐Qiang Chu Hua Meng Prof. Dr. Xiao‐Ping Xu Prof. Dr. Shun‐Jun Ji 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(32):11359-11368
A metal‐free tandem procedure by using a sulfonylation reaction of aryl allylic alcohols followed by an iodobenzenediacetate (PIDA)‐promoted oxidative functionalization has been established. Allylic sulfones, γ‐ketosulfones, and triflyl allylic alcohols have been constructed in a single operation. The methodology incorporates the sulfonyl (both aryl and triflyl) functionality with a simple work‐up procedure. 相似文献
6.
烯丙位氧化的几种方法 总被引:4,自引:0,他引:4
综述了近年来烯丙位氧化的研究进展,详细讨论了过渡金属及其络合物、硒化 合物在烯丙位氧化中的应用,并简述了丁基锂方法、固相催化方法、生物氧化方法 和次氯酸钠氧化方法在烯丙位氧化中的应用. 相似文献
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In this article, a study on reactions of tertiary allylic amines and dichlorocarbenes had been described. Tertiary allylic amines could result from an interesting de-N-allylation/formylation reaction under the treatment of dichlorocarbenes. Notably, amines containing steric substituents or electron-deficient aromatic substituents on the nitrogen will go through cyclopropanations of the carbon–carbon double bond. 相似文献
9.
Xiaoyun Wu Dr. Wei Ma Prof. Dr. Weijun Tang Prof. Dr. Dong Xue Prof. Dr. Jianliang Xiao Prof. Dr. Chao Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(60):e202201829
Allylic amines are useful building blocks in organic synthesis, so the development of green and efficient methods for the preparation of allylic amines are of great importance. An Fe-catalyzed amidation of allylic alcohols with chiral tert-butylsulfinamide has been developed. With water as the only by-product, a range of synthetically useful chiral sulfinamide olefin derivatives (30 examples) were obtained under mild reaction conditions. The reaction can be performed on a gram-scale, and the products could serve as chiral ligands for asymmetric catalysis. Mechanistic studies suggest that the reaction proceeds by an Fe-catalyzed borrowing hydrogen process, which is different from most of the reported allylic amination reactions. 相似文献
10.
Bencong Zhu Tao Shen Xiaoqiang Huang Yuchao Zhu Song Song Ning Jiao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(32):11144-11148
Aerobic epoxidation of tertiary allylic alcohols remains a significant challenge. Reported here is an efficient and highly chemoselective copper‐catalyzed epoxidation and semipinacol rearrangement reaction of tertiary allylic alcohols with molecular oxygen. The solvent 1,4‐dioxane activates dioxygen, thereby precluding the addition of a sacrificial reductant. 相似文献
11.
Atom-efficient stoichiometric silylcupration reactions of acetylenes followed by electrophilic trapping of the intermediate vinylcopper species with allylic phosphates have been developed. The reaction sequence was also carried out with the use of a catalytic amount of CuCN employing of both allylic phosphates and allylic phosphinates as electrophiles. The methods developed provide an easy access to silylated 1,4-diene systems. 相似文献
12.
Lilly MJ Miller NA Edwards AJ Willis AC Turner P Paddon-Row MN Sherburn MS 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(8):2525-2536
The stereochemical outcome of the intramolecular Diels-Alder reaction of ester-linked 1,3,8-nonatrienes can be controlled by substituents about a stereogenic center attached to C1. The scope and limitations of this approach have been investigated, with variation in substrate structure about the allylic stereocenter and the dienophile. The stereochemical outcomes of these reactions are explained by reference to B3 LYP/6-31G(d) transition structures. New insights into the conformational preferences of allylic alcohol derivatives are reported, results which allow an explanation of the differing levels of pi-diastereofacial selectivity and cis/trans (i.e. endo/exo) selectivity from the reaction. 相似文献
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Fuad O. Usman Achyut R. Gogoi Dr. Jason C. Mixdorf Prof. Dr. Osvaldo Gutierrez Prof. Dr. Hien M. Nguyen 《Angewandte Chemie (International ed. in English)》2023,62(48):e202314843
Although there are many methods for the asymmetric synthesis of monosubstituted allylic fluorides, construction of enantioenriched 1,2-disubstituted allylic fluorides has not been reported. To address this gap, we report an enantioselective synthesis of 1,2-disubstituted allylic fluorides using chiral diene-ligated rhodium catalyst, Et3N ⋅ 3HF as a source of fluoride, and Morita Baylis Hillman (MBH) trichloroacetimidates. Kinetic studies show that one enantiomer of racemic MBH substrate reacts faster than the other. Computational studies reveal that both syn and anti π-allyl complexes are formed upon ionization of allylic substrate, and the syn complexes are slightly energetically favorable. This is in contrast to our previous observation for formation of monosubstituted π-allyl intermediates, in which the syn π-allyl conformation is strongly preferred. In addition, the presence of an electron-withdrawing group at C2 position of racemic MBH substrate renders 1,2-disubstituted π-allyl intermediate formation endergonic and reversible. To compare, formation of monosubstituted π-allyl intermediates was exergonic and irreversible. DFT calculations and kinetic studies support a dynamic kinetic asymmetric transformation process wherein the rate of isomerization of the 1,2-disubstituted π-allylrhodium complexes is faster than that of fluoride addition onto the more reactive intermediate. The 1,2-disubstituted allylic fluorides were obtained in good yields, enantioselectivity, and branched selectivity. 相似文献
15.
Allylic substitution of allylic cyclic carbonates with PhSH or PhOH in the presence of CpRu(PPh3)2Cl (5 mol %) afforded (E)-allylic alcohol and erythro-β-hydroxy thiophenoxide or phenoxide respectively, via external attack of nucleophiles to π-allyl ruthenium complex. 相似文献
16.
Dr. J. Caleb Hethcox Samantha E. Shockley Prof. Dr. Brian M. Stoltz 《Angewandte Chemie (International ed. in English)》2016,55(52):16092-16095
The development of the first enantio‐, diastereo‐, and regioselective iridium‐catalyzed allylic alkylation reaction of prochiral enolates to form an all‐carbon quaternary stereogenic center with an aliphatic‐substituted allylic electrophile is disclosed. The reaction proceeds with good to excellent selectivity with a range of substituted tetralone‐derived nucleophiles furnishing products bearing a newly formed vicinal tertiary and all‐carbon quaternary stereodyad. The utility of this protocol is further demonstrated via a number of synthetically diverse product transformations. 相似文献
17.
Asymmetric Allylic Alkylation of β‐Ketoesters with Allylic Alcohols by a Nickel/Diphosphine Catalyst
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Dr. Yusuke Kita Dr. Rahul D. Kavthe Hiroaki Oda Prof. Dr. Kazushi Mashima 《Angewandte Chemie (International ed. in English)》2016,55(3):1098-1101
Asymmetric allylic alkylation of β‐ketoesters with allylic alcohols catalyzed by [Ni(cod)2]/(S)‐H8‐BINAP was found to be a superior synthetic protocol for constructing quaternary chiral centers at the α‐position of β‐ketoesters. The reaction proceeded in high yield and with high enantioselectivity using various β‐ketoesters and allylic alcohols, without any additional activators. The versatility of this methodology for accessing useful and enantioenriched products was demonstrated. 相似文献
18.
Dr. Satoru Arimitsu 《Chemical record (New York, N.Y.)》2023,23(9):e202300021
This account presents the synthesis and application of propargylic and allylic fluorides containing hydroxy or carbonyl functional groups. In particular, the Barbier-type reaction of difluoropropargyl bromides with aldehydes or chloroformates provides versatile propargylic fluorides, and the organocatalytic fluorination of dienamine intermediates has been demonstrated as an effective method to obtain allylic fluorides stereoselectively. Additionally, mechanistic insights into such reactions are discussed with the aid of density functional theory calculations. The report also describes the preparation of fluorinated 1,7-diyne or 1,7-enyne derivatives of these compounds. These propargylic and allylic fluorides can be used as building blocks for fluorinated heterocycles, such as fluorinated furans, tetrahydrofurans, and lactams. Additionally, fluorinated bi- or tri-heterocyclic compounds can be synthesized via transition-metal-catalyzed reactions with fluorinated 1,7-diyne or 1,7-enyne derivatives. 相似文献
19.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(32):9645-9649
A catalytic intermolecular allylic C−H trifluoromethoxylation reaction of alkenes has been developed based on the use of a palladium catalyst, CsOCF3 as the trifluoromethoxide source, and benzoquinone as the oxidant. This reaction provides an efficient route for directly accessing allylic trifluoromethoxy derivatives with excellent regioselectivities from terminal alkenes via an allylic C−H bond activation process. 相似文献
20.
Synthesis of Branched Alkylboronates by Copper‐Catalyzed Allylic Substitution Reactions of Allylic Chlorides with 1,1‐Diborylalkanes
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Junghoon Kim Sangwoo Park Jinyoung Park Prof. Dr. Seung Hwan Cho 《Angewandte Chemie (International ed. in English)》2016,55(4):1498-1501
Reported herein is a copper‐catalyzed SN2′‐selective allylic substitution reaction using readily accessible allylic chlorides and 1,1‐diborylalkanes, a reaction which proceeds with chemoselective C?B bond activation of the 1,1‐diborylalkanes. In the presence of a catalytic amount of [Cu(IMes)Cl] [IMes=1,3‐bis(2,4,6‐trimethylphenyl)imidazole‐2‐ylidene] and LiOtBu as a base, a range of primary and secondary allylic chlorides undergo the SN2′‐selective allylic substitution reaction to produce branched alkylboronates. The synthetic utilities of the obtained alkylboronates are also presented. 相似文献