Showing papers on "Total synthesis published in 1990"
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20 Dec 1990
TL;DR: In this paper, the authors present a list of the most important steps in the development of catalytic catalysts for organic synthesis, including the transition metal-catalyzed functionalization of Alkanes.
Abstract: Preface.List of Contributors.PART I. SYNTHETIC METHODS.Direct Conversion of Sugar Glycosides into Carbocycles (Peter I. Dalko and Pierre Sinay).Synthesis of Diaryl Ethers: A Long-Standing Problem Has Been Solved (Fritz Theil).Take The Right Catalyst: Palladium-Catalyzed CC-, CN- and CO-Bond Formation on Chloro-Arenes (Rainer Stumer).Alkyne Metathesis in Natural Product Synthesis (Thomas Lindel).Transition Metal-Catalyzed Functionalization of Alkanes (Oliver Seitz).An Eldorado for Homogeneous Catalysis? (Gerald Dyker).New and Selective Transition Metal Catalyzed Reactions of Allenes (A. Stephen K. Hashmi).Controlling Stereoselectivity with the Aid of a Reagent-Directing Group (Bernhard Breit).Solvent-Free Organic Syntheses (Jurgen O. Metzger).Fluorous Techniques: Progress in Reaction-Processing and Purification (Ulf Diederichsen).Recent Developments in Using Ionic Liquids as Solvents and Catalysts for Organic Synthesis (Peter Wasserscheid).Recent Advances on the Sharpless Asymmetric Aminohydroxylation (Dmitry Nilov and Oli ver Reiser).Asymmetric Phase Transfer Catalysis (Christabel Carter and Adam Nelson).Asymmetric Catalytic Aminoalkylations: New Powerful Methods for the Enantioselective Synthesis of Amino Acid Derivatives, Mannich Bases, and Homoallylic Amines (Michael Arend and Xiaojing Wang).IBX - New Reactions with an Old Reagent (Thomas Wirth).Parallel Kinetic Resolutions (Jason Eames).The Asymmetric Baylis-Hillman-Reaction (Peter Langer).Simple Amino Acids and Short-Chain Peptides as Efficient Metal-free Catalysts in Asymmetric Syntheses (Harald Groger, et al.).Recent Developments in Catalytic Asymmetric Strecker-Type Reactions (Larry Yet).Highly Enantioselective or Not? - Chiral Monodentate Monophosphorus Ligands in the Asymmetric Hydrogenation (Igor V. Komarov and Armin Borner).Improving Enantioselective Fluorination Reactions: Chiral N-Fluoro Ammonium Salts and Transition Metal Catalysts (Kilian Muniz).Catalytic Asymmetric Olefin Metathesis (Amir H. Hoveyda and Richard R. Schrock).Activating Protecting Groups for the Solid Phase Synthesis and Modification of Peptides, Oligonucleotides and Oligosaccharides (Oliver Seitz).Traceless Linkers for Solid-Phase Organic Synthesis (Florencio Zaragoza Dorwald).Merging Solid-Phase and Solution-Phase Synthesis: The "Resin-Capture- Release" Hybrid Technique (Andreas Kirschning and Rudiger Wittenberg).Polymeric Scavenger Reagents in Organic Synthesis (Jason Eames and Michael Watkinson).PART II. APPLICATIONS.Total Syntheses of Vancomycin (Lars H. Thoresen and Kevin Burgess).Bryostatin and Their Analogues (Ulf Diederichsen).Eleutherobin: Synthesis, Structure/Activity Relationship, and Pharmacophore (Ulf Diederichsen).Total Synthesis of the Natural Products CP-263,114 and CP-225,917 (Ulf Diederichsen and Katrin B. Lorenz).Polyene Cyclization to Adociasulfate 1 (Thomas Lindel and Cordula Hopmann).Sanglifehrin A: An Immunosuppressant Natural Product from Malawi (Thomas Lindel).Short Syntheses of the Spirotryprostatins (Thomas Lindel).The Chemical Total Synthesis of Proteins (Oliver Seitz).Solid-Phase Synthesis of Oligosaccharides (Ulf Diederichsen and Thomas Wagner).Polymer-Supported Synthesis of Non-Oligomeric Natural Products (Stefan Sommer, et al.).Explosions as a Synthetic Tool? Cycloalkynes as Precursors to Fullerenes, Buckytubes and Buckyonions (Rudiger Faust).Dendralenes: From a Neglected Class of Polyenes to Versatile Starting Materials in Organic Synthesis (Henning Hopf).Fascinating Natural and Artificial Cyclopropane Architectures (Rudiger Faust).Index.
384 citations
261 citations
TL;DR: A convergent asymmetric synthesis of the antinoeplastic macrolide antibiotic cytovaricin has been achieved through the synthesis and coupling of the illustrated spiroketal and polyol glycoside subunits.
Abstract: A convergent asymmetric synthesis of the antinoeplastic macrolide antibiotic cytovaricin has been achieved through the synthesis and coupling of the illustrated spiroketal and polyol glycoside subunits. All absolute steroechemical relationships within the target structure were ultimately controlled by the use of asymmetric aldol, alkylation, or epoxidation methodology. Union of the two subnits was accomplished by Julia-Lythgoe trans olefination, providing direct access to a suitable macrolactonization substrate
261 citations
258 citations
TL;DR: A convergent asymmetric synthesis of the calcium ionophore ionomycin has been achieved through a route that is outlined in this paper, where the four illustrated subunits, which comprise the c,C,,-,, CI)-&r cI&22, and C=-C32 portions of ionomecin, are presented.
Abstract: A convergent asymmetric synthesis of the calcium ionophore ionomycin has been achieved through a route that is outlined below. The four illustrated subunits, which comprise the c,-C,,-,, CI)-&r cI&22, and C=-C32 portions of ionomycin,
195 citations
TL;DR: In this paper, the chemistry of the tricarbonyl region of FK-506 and its use in designing a sucessful route to this immunosuppressant is outlined.
Abstract: Details of model studies probing the chemistry of the tricarbonyl region of FK-506 are presented, and their use in designing a sucessful route to this immunosuppressant is outlined. Applications of asymmetric oxazolidinone alkylation/aldol methodology to a convergent, highly flexible synthesis of the C 10 -C 18 fragment and to improvements in the preparation of the C 20 ―C 34 segment are also discussed
181 citations
TL;DR: The complete synthesis of chlorophyll a starting from Knorr's pyrrole was described in detail in this article, with full experimental detail, in which the four pyrroles which are required for rings A, B, C and D were elaborated largely by known reactions, although with considerable improvements.
172 citations
TL;DR: In this article, an asymmetric, stereocontrolled total synthesis of (−)-brevianamide B (2) is described, which features a sterecontrolled intramolecular S N 2' cyclization to construct the central bicyclo[2.2] nucleus.
Abstract: The asymmetric, stereocontrolled total synthesis of (−)-brevianamide B (2) is described. The synthesis features a sterecontrolled intramolecular S N 2' cyclization to construct the central bicyclo[2.2.2] nucleus. A synthetic route to C-10-epibrevianamide A (49) is also described
127 citations
TL;DR: In this paper, the authors proposed that disconnections between L-leucine and the HIP group (2S, 4S) and between Lthreonine and isostatine (3S,4R, 5S) would afford two units: a HIP-isostatines unit (I) and a tetrapeptide unit (II) respectively.
Abstract: Didemnins A, B, and C were efficiently prepared in a stereocontrolled manner, producing the common macrocycle and, in a separate step, introducing the substituents on the amino group of L-threonine as optically pure units. We envisaged that disconnections between L-leucine and the HIP group (2S,4S) and between L-threonine and isostatine (3S,4R,5S) would afford two units: a HIP-isostatine unit (I) and a tetrapeptide unit (II)
123 citations
TL;DR: The first enantiospecific synthesis of (+)-macbecin I has been performed in a convergent manner by coupling the epoxide (3) with a higher order cyanocuprate derived from the vinyl iodide (46) as mentioned in this paper.
Abstract: The first total enantiospecific synthesis of (+)-macbecin I has been performed in a convergent manner by coupling the epoxide (3) with a higher order cyanocuprate derived from the vinyl iodide (46). The required absolute stereochemistries at C(20)–C(21) and C(12)–C(13) were accessible by enantioselective aldol condensations while that at C(16)–C(17) was achieved by Sharpless epoxidation of a secondary (E)-allylic alcohol (39), efficiently prepared by reaction of the aldehyde (37) with CrCl2-CH3CHI2. The remaining stereocentre at C-18 was introduced by an asymmetric hydroxylation of an enolate. Macrocyclization of the amino acid (59) to give the lactam (60) was successfully achieved by its reaction with either 2-mesitylenesulphonyl chloride or bis(2-oxo-3-oxazolidinyl)phosphinic chloride. Incorporation of the carbamate functionality was achieved by reaction of the parent hydroxy derivative with sodium cyanate and trifluoroacetic acid. The final oxidation to the quinone was accomplished with cerium(IV) ammonium nitrate.
123 citations
TL;DR: The 4-O-Benzyl-23-Oisopropylidene-L-threose building block is a useful four-carbon building block for monosaccharide synthesis as discussed by the authors.
TL;DR: In this article, a reiterative two-carbon extension cycle consisting of four key transformations is used to synthesize polyhydroxylated natural products using a four-key extension cycle.
TL;DR: In this article, total synthesis of (±)-tazettine (1) and 6a-epipretazettines (3) was reported in 11 steps from the known enal 7 (14 steps from commercially available p-methoxybenzyl alcohol), with excellent yield (63-90%) and high stereo-induction (>20:1) to form 14
Abstract: Total syntheses of (±)-tazettine (1) and (±)-6a-epipretazettine (3), which proceed in 11 steps from the known enal 7 (14 steps from commercially available p-methoxybenzyl alcohol), are reported. The pivotal step is the palladium-catalyzed cyclization of alkenyl aryl iodide 13, which proceeded in excellent yield (63-90%) and with high stereoinduction (>20:1) to form 14
TL;DR: In this article, the oxazoline-mediated biaryl coupling reaction was applied successfully to the total synthesis of a series of dibenzocyclooctadiene lignans in chiral nonracemic form.
Abstract: The oxazoline-mediated biaryl coupling reaction was applied successfully to the total synthesis of a series of dibenzocyclooctadiene lignans in chiral nonracemic form. The diastereoselectivities achieved in the coupling reaction varied in a predictable manner, primarily as a function of the ortho substituents on the phenyl Grignard reagent
TL;DR: The synthesis of (±)-jatrophone and its epimer was completed with use of a palladium-catalyzed carbonylative coupling of a vinylic triflate with an organostannane as the key step as discussed by the authors.
Abstract: Jatrophone is a macrocyclic diterpene which exhibits significant inhibitory activity in vivo and in vitro against various carcinomas. The synthesis of (±)-jatrophone and its epimer was completed with use of a palladium-catalyzed carbonylative coupling of a vinylic triflate with an organostannane as the key step. The synthesis of epi-jatrophone was first completed to establish the chemistry for jatrophone. The overall sequence for each synthesis required 16 steps starting from 4-methyl-2-cyclopenten-1-one. The overall yields were 0.83% and 0.28%, respectively
TL;DR: In this article, the authors presented an optically pure α-tert-butyl β-methyl (2S,3R)-3-ethylhexahydroquinolinate (EHQ) in 54-59% yield from L-aspartic acid was the foundation for a practical synthesis of (+)-vincamine.
Abstract: Synthesis of optically pure α-tert-butyl β-methyl (2S,3R)-3-ethylhexahydroquinolinate (18) in 54-59% yield from L-aspartic acid was the foundation for a practical synthesis of (+)-vincamine. This synthesis provides (+)-vincamine, demonstrated to be >99% enantiomerically pure, in 24-26% overall yield from L-aspartic acid
TL;DR: In this paper, an asymmetric version of the previously published synthesis of methyl homosecodaphniphyllate (2) was obtained by adding the lithium enolate of the C 2 -symmetric amide to α,β-unsaturated ester to give ester amide 12.
Abstract: (-)-Secodaphniphylline (1) has been prepared by total synthesis. The early stages,of the synthesis were an asymmetric version of the previously published synthesis of methyl homosecodaphniphyllate (2). The necessary chirality was secured by an asymmetric Michael addition reaction of the lithium enolate of the C 2 -symmetric amide 9 to α,β-unsaturated ester 10 to give ester amide 12. The conversion of 12 into (-)-2 was modelled after the previously reported synthesis in the analogous racemic series
TL;DR: In this paper, the IL-V was prepared in 10 steps from L-tryptophan methyl ester in 17.1% overall yield, with the key steps involved regiospecific thallation of the acylindole intermediate.
TL;DR: In this article, a new synthetic entry to pentacyclic Strychnos alkaloids has been successfully developed, and the crucial step of the synthesis consists in the closure of the five-membered E ring by cyclization upon the indole 3-position.
Abstract: Thus, a new synthetic entry to pentacyclic Strychnos alkaloids that has allowed the total synthesis of (±)-tubifolidine, (±)-tubifoline, and (±)-19,20-dihydroakuammicine has been successfully developed. The crucial step of the synthesis consists in the closure of the five-membered E ring (bond formed C-6/C-7) by cyclization upon the indole 3-position
TL;DR: The bridged, pentacyclic intermediate 2 for atisine was synthesized in a naturally occurring enantiomeric form from dimethyl cyclohexanone-2,6-dicarboxylate (6) as mentioned in this paper.
Abstract: The bridged, pentacyclic intermediate 2 for atisine (1) was synthesized in a naturally occurring enantiomeric form from dimethyl cyclohexanone-2,6-dicarboxylate (6). The synthesis is composed of the following key steps: (1) formation of the azabicyclo [3.3.1] nonane by a double Mannich reaction, (2) enantioselective conversion by a lipase-catalyzed acylation, (3) stereoselective hydroboration in the presence of BF 3 .Et 2 O, and (4) construction of the bicyclo [2.2.2] octane ring system by an intramolecular double Michael reaction
TL;DR: In this paper, a stereocontrolled synthesis of hypocholesterolemic compounds, namely, compactin(+)-mevinolin, was described for the first time.
Abstract: A strategy is described for stereocontrolled synthesis of hypocholesterolemic compounds, (+)-compactin(+)-mevinolin
TL;DR: Methylation ou hydroxylation en C 3 de flavones hautement substituees et de styrylchromones, de facon tres regioselective par le diisopropylamide et suivie de piegeage par un electrophile as mentioned in this paper.
Abstract: Methylation ou hydroxylation en C 3 de flavones hautement substituees et de styrylchromones, de facon tres regioselective par le diisopropylamide et suivie de piegeage par un electrophile. Obtention de produit 3-methyl ou 3-hydroxy. Une synthese totale du compose naturel hormothamnione styrylchromone, contenant un substituant 3-methyl est decrite selon cette technique
TL;DR: In this article, a new nouveau sulfinyl orthoacetate was used for conversion, dans un seul vase a reaction, de certains alcools allyliques en esters dienoates correspondants via des rearrangements de Claisen et β-elimination de sulfoxyde a 100 o C
Abstract: Utilisation d'un nouveau sulfinyl orthoacetate pour la conversion, dans un seul vase a reaction, de certains alcools allyliques en esters dienoates correspondants via des rearrangements de Claisen et β-elimination de sulfoxyde a 100 o C
TL;DR: Medermycin has been first synthesized from D -rhamnose derivatives and was later confirmed to be identical with lactoquinomycin in this paper, and was shown to be stable in vitro.