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1.
Chhor RB Nosse B Sörgel S Böhm C Seitz M Reiser O 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(1):260-270
The development of a new method for the enantioselective synthesis of disubstituted gamma-butyrolactones is reported. Based on this strategy, the total synthesis of three paraconic acids, that is (-)-roccellaric acid, (-)-nephrosteranic acid and (-)-protopraesorediosic acid, and the formal total synthesis of (-)-methylenolactocin and (-)-protolichesterinic acid is described, which are important because of their antibiotic and antitumor properties. Key steps of the synthesis are copper(I)-catalyzed asymmetric cyclopropanations of furans, highly diastereoselective Sakurai allylations, Lewis acid or Lewis base catalyzed retroaldol/lactonization cascades, and ruthenium(II)-catalyzed, intermolecular cross metathesis reactions. 相似文献
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Strained nitroso Diels–Alder bicyclo[2.2.1] or [2.2.2] adducts functionalized with alkene side chains of diverse length undergo a ring‐rearrangement metathesis process with external alkenes and Grubbs II or Hoveyda–Grubbs II ruthenium catalysts, under microwave irradiation or classical heating, to deliver cis‐fused bicycles of various ring sizes, which contain a N? O bond. These scaffolds are of synthetic relevance for the generation of molecular diversity and to the total synthesis of alkaloids. The observation of unexpected reactions, such as epimerization or one‐carbon homologation of the alkene side chain, is also reported. 相似文献
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Sambasivarao Kotha Milind Meshram Nageswara Rao Panguluri Vrajesh R. Shah Saidulu Todeti Mukesh E. Shirbhate 《化学:亚洲杂志》2019,14(9):1356-1403
Herein, we summarize the synthetic approaches that have been developed for the synthesis of star‐shaped molecules. Typically, to design such highly functionalized molecules, simple building blocks are first assembled through trimerization reactions, starting from commercially available starting materials. Then, these building blocks are synthetically manipulated to generate extended star‐shaped molecules. We also discuss the syntheses of star‐shaped molecules that contain 2,4,6‐trisubstituted 1,3,5‐triazine or 1,3,5‐trisubstituted benzene rings as a central core and diverse substituted styrene, phenyl, and fluorene derivatives at their periphery, which endows these molecules with extended conjugation. A variety of metal‐catalyzed reactions, such as Suzuki, Buchwald–Hartwig, Sonogashira, Heck, and Negishi cross‐coupling reactions, as well as metathesis, have been employed to functionalize a range of star‐shaped molecules. The methods described herein will be helpful for designing a wide range of intricate compounds that are highly valuable in the fields of supramolecular chemistry and materials science. Owing to space limitations, we will not cover all of the publications on this topic. Instead, we will focus on examples that were reported by our research group and other relevant recent literature. Apart from the trimerization sequence, this Minireview has been structured based on the key reactions that were used to prepare the star‐shaped molecules and other higher analogues. Finally, some examples that do not fit into this classification are discussed. 相似文献
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Riva E Rencurosi A Gagliardi S Passarella D Martinelli M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(22):6221-6226
An efficient total synthesis of the natural alkaloid (+)-dumetorine by using flow technology is described. The process entailed five separate steps starting from the enantiopure (S)-2-(piperidin-2-yl)ethanol 4 with 29% overall yield. Most of the reactions were carried out by exploiting solvent superheating and by using packed columns of immobilized reagents or scavengers to minimize handling. New protocols for performing classical reactions under continuous flow are disclosed: the ring-closing metathesis reaction with a novel polyethylene glycol-supported Hoveyda catalyst and the unprecedented flow deprotection/Eschweiler-Clarke methylation sequence. The new protocols developed for the synthesis of (+)-dumetorine were applied to the synthesis of its simplified natural congeners (-)-sedamine and (+)-sedridine. 相似文献
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Total synthesis of THP tethered pyrone containing natural product cryptopyranmoscatone B2 was accomplished from commercially available 2-deoxyribose. The key THP unit was assembled by FeCl3 catalyzed cyclization of an allyl alcohol. Brown allylation and RCM reactions were employed to construct the lactone unit. The synthesis represents the first total synthesis of the putative structure of the natural product. 相似文献
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Dr. Amit B. Pawar Prof. Dr. Kavirayani R. Prasad 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(47):15202-15206
A formal total synthesis of the 20‐membered marine macrolide, palmerolide A from chiral pool tartaric acid is described. Elaboration of a γ‐hydroxy amide, which is derived from the desymmetrization of tartaric acid amide, and Boord olefination are the pivotal reactions employed for the synthesis of the chiral building blocks, and Stille coupling and ring‐closing metathesis (RCM) are used to assemble the macrolactone. 相似文献
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Nagaraju Madala Venkata Rao Ghanta Srilalitha Vinnakota Narender Mendu Arun B. Ingle Krishna Ethiraj Vishal Sharma 《Tetrahedron letters》2018,59(27):2708-2710
A synthetic strategy was developed for the synthesis of the common core structure of Carpatamides A–D. The total synthesis of Carpatamides A and C was completed in 6 steps and of Carpatamides B and D in 7 steps, by employing the Wittig olefination, olefin cross metathesis and acid amine coupling reactions as key steps. 相似文献
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A stereoselective total synthesis of L-783,290 has been achieved involving Alder–Rickert reaction, ring closing metathesis, and chemoselective oxidation as key steps. This approach has successfully demonstrated a linear sequence of reactions, which are highly stereoselective for the construction of the resorcylic acid unit. 相似文献
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Ene–yne cross metathesis was assessed for use as a key fragment coupling in a planned total synthesis of amphidinolide P. A terminal alkyne containing a β,γ-epoxide was synthesized and employed as the alkyne partner in an intermolecular ene–yne metathesis. In the alkene substrate, optimal functionality and reaction conditions were determined. An unprotected allyl alcohol was found to be critical for both high yield and high E-selectivity. Fewer equivalents of the alkene resulted in incomplete reaction and side reactions consumed the terminal alkyne. The best ruthenium carbene precatalysts were found to be the Hoveyda–Grubbs carbene complexes. 相似文献
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Tobias Biberger Szabolcs Makai Dr. Zhong Lian Dr. Bill Morandi 《Angewandte Chemie (International ed. in English)》2018,57(23):6940-6944
Among all metathesis reactions known to date in organic chemistry, the metathesis of multiple bonds such as alkenes and alkynes has evolved into one of the most powerful methods to construct molecular complexity. In contrast, metathesis reactions involving single bonds are scarce and far less developed, particularly in the context of synthetically valuable ring‐closing reactions. Herein, we report an iron‐catalyzed ring‐closing metathesis of aliphatic ethers for the synthesis of substituted tetrahydropyrans and tetrahydrofurans, as well as morpholines and polycyclic ethers. This transformation is enabled by a simple iron catalyst and likely proceeds via cyclic oxonium intermediates. 相似文献
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Mikko Passiniemi 《Tetrahedron letters》2008,49(6):980-983
A short total synthesis of the cytotoxic natural product pachastrissamine is described. The synthesis includes eight steps starting from Garner’s aldehyde and proceeds in 20% overall yield. Pd(0)-mediated intramolecular cyclisation and Ru-mediated cross-metathesis are the key reactions in this sequence. 相似文献
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Dr. Benjamin J. Moritz Dr. Daniel J. Mack Liuchuan Tong Prof. Regan J. Thomson 《Angewandte Chemie (International ed. in English)》2014,53(11):2988-2991
The total synthesis of sculponeatin N, a bioactive polycyclic diterpene isolated from Isodon sculponeatus, is reported. Key features of the synthesis include diastereoselective Nazarov and ring‐closing metathesis reactions, and a highly efficient formation of the bicyclo[3.2.1]octane ring system by a reductive radical cyclization. 相似文献
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A simple and efficient total synthesis of patulolide A from readily available 7-octen-1-ol is reported by asymmetric synthetic approach. The key reactions involved are asymmetric dihydroxylation using AD-mix-β and Grubbs’ ring-closing metathesis reaction for the synthesis macrocyclic ring system. 相似文献
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A simple and efficient stereoselective total synthesis of sporiolide B and attempted synthesis of sporiolide A, from epichlorohydrin, using asymmetric synthetic approach is reported. The key reactions involved are Sharpless epoxidation, Jacobsen reaction, syn-allylation, Yamaguchi esterification, and Grubbs ring-closing metatheses reaction to result in the macrocyclic ring system. 相似文献
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Lian‐Dong Guo Xiong‐Zhi Huang Shi‐Peng Luo Wen‐Sen Cao Prof. Yuan‐Ping Ruan Dr. Jian‐Liang Ye Prof. Dr. Pei‐Qiang Huang 《Angewandte Chemie (International ed. in English)》2016,55(12):4064-4068
The first total synthesis of the alkaloid (?)‐haliclonin A is reported. The asymmetric synthesis relied on a novel organocatalytic asymmetric conjugate addition of nitromethane with 3‐alkenyl cyclohex‐2‐enone to set the stereochemistry of the all‐carbon quaternary stereogenic center. The synthesis also features a Pd‐promoted cyclization to form the 3‐azabicyclo[3,3,1]nonane core, a SmI2‐mediated intermolecular reductive coupling of enone with aldehyde to form the requisite secondary chiral alcohol, ring‐closing alkene and alkyne metathesis reactions to build the two aza‐macrocyclic ring systems, and an unprecedented direct transformation of enol into enone. 相似文献
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Gradillas A Pérez-Castells J 《Angewandte Chemie (International ed. in English)》2006,45(37):6086-6101
The construction of macrocycles by ring-closing metathesis (RCM) is often used as the key step in the synthesis of natural products containing large rings. This reaction is attractive because of its high functional group compatibility and the possibility for further transformations. The finding of suitable reaction conditions is critical for the success of the synthesis. In this Minireview we summarize the efforts of many research groups to develop efficient RCM reactions on their way towards the total synthesis of natural macrocyclic products. Their findings should help in future synthesis to reduce the time-consuming phase of the optimization of the reaction conditions. 相似文献
18.
Prashant K. Metri 《合成通讯》2020,50(9):1361-1366
AbstractFormal total synthesis of dihydrokawain-5-ol is accomplished starting from tartaric acid. Key reactions include Horner–Wadsworth–Emmons olefination, sodium borohydride mediated stereoselective reduction, orthogonal protection and deprotection of alcohols and ring closing metathesis. 相似文献
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Total synthesis of trocheliophorolide C epimer is reported. The synthetic strategy involves generation of lactone skeleton and preparation of unsaturated side chain followed by cross-metathesis. The Eglinton oxidative coupling, Cadiot-Chodkiewicz cross-coupling and cross-metathesis are the key reactions used in the synthesis. We also attempted the synthesis of trocheliophorolide D epimer, which includes Cu catalyzed various cross-coupling reactions. 相似文献
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The first stereoselective total synthesis of gamahonolide A (1) has been accomplished using aminoxylation, Keck allylation, and ring-closing metathesis (RCM) reactions as key steps. 相似文献