Showing papers on "Claisen rearrangement published in 1988"
448 citations
136 citations
TL;DR: The results demonstrate the feasibility of using rationally designed immunogens to generate antibodies that catalyze concerted reactions that catalyzes rearrangement of chorismate to prephenate.
Abstract: Monoclonal antibodies were prepared against a transition state analog inhibitor of chorismate mutase (EC 5.4.99.5). One of the antibodies catalyzes the rearrangement of chorismate to prephenate with rate accelerations of more than 2 orders of magnitude compared to the uncatalyzed reaction. Saturation kinetics were observed, and at 25 degrees C the values of kcat and Km were 1.2 X 10(-3) s-1 and 5.1 X 10(-5) M respectively. The transition state analog was shown to be a competitive inhibitor of the reaction with Ki equal to 0.6 microM. These results demonstrate the feasibility of using rationally designed immunogens to generate antibodies that catalyze concerted reactions.
134 citations
109 citations
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TL;DR: In this paper, an α-Amino acids with allenyl, vinyl, and acetylenic side chains can be synthesized using non-enolate based strategies.
78 citations
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TL;DR: The chiral aldehyde 7 was prepared by diastereoselective alkylation, subsequent 1,2- addition of isopropenylmagnesium bromide gave rise to a mixture (68:32) of the allylic alcohols 8 and 10 which was separated by recycling MPLC.
35 citations
TL;DR: In this paper, the ratio of the two ortho rearrangement products was dependent both on the length of the alkoxy substituent and on that of the host cavity suggesting that, subtle and rationale engineering manipulation is required to achieve exclusive obtention of only one ortho isomer.
TL;DR: Synthese a partir de bromoacetyl-5 benzodioxole-1,3 et d'ethoxy-2 pyrroline-1 carboxylate-5 d'ETHyle.
Abstract: Synthese a partir de bromoacetyl-5 benzodioxole-1,3 et d'ethoxy-2 pyrroline-1 carboxylate-5 d'ethyle (prepare a partir d'acide pyroglutamique)
TL;DR: In this paper, a general approach to the synthesis of iridoid aglycones is reported, where a combination of Claisen rearrangement/nitrile oxide cycloaddition sequence has permitted the facile annulation of a highly functionalized cyclopentane ring onto a simple glycal derived from D-xylal.
TL;DR: In this paper, a photo-oxidation of 1-methoxy carbazolequinone gave murrayaquinone-B (2) and pyranocarbazole (21), which failed to yield the related pyrayaquinone-b (6).
Abstract: A synthesis of the carbazolequinone alkaloid murrayaquinone-B (2) is described. The route to the 1-methoxycarbazole (14a) involves a regioselective Claisen rearrangement to give the 7-(3-methylbut-2-enyl)indole (9a), and formation of the third ring of compound (14a) by cyclisation of the aldehyde (13a), which is prepared from the lactone (11a)(Scheme 1). The methoxycarbazole (14b), which lacks three methyl groups, was prepared by a similar route. Photo-oxidation of the carbazole (14a) gave murrayaquinone-B (2), although a similar photo-oxidation of the pyranocarbazole (21), prepared in an analogous manner (Scheme 2), failed to yield the related carbazolequinone alkaloid, pyrayaquinone-B (6).
TL;DR: In this paper, a one-pot synthesis of 4-chlorochromenes and chroman-4-ones was achieved from γ-chloropropargyl aryl ethers proceeding through Claisen rearrangement, depending upon the solvent of choice.
TL;DR: The first synthesis of agelasidine A (1) was accomplished in 8 steps starting from farnesol as discussed by the authors, and the quaternary carbon atom was constructed by the successful application of the hetero-Claisen rearrangement of allyl xanthate.
TL;DR: The sequence: group transfer Michael addition, aldol / lactonization and Claisen rearrangement provides access to the title compounds as discussed by the authors, which is the sequence used in this paper.
TL;DR: In this article, a facile Claisen rearrangement in N,N-diethylaniline/o-dichlorobenzene was proposed to give flav-3-enes in good yields.
TL;DR: Synthese d'un derive de taxane a partir d'une dibenzo [c,g] oxecinne issue d'one cyclohexenylydenehydrazide d'acide benzene sulfonique
Abstract: Synthese d'un derive de taxane a partir d'une dibenzo [c,g] oxecinne issue d'un cyclohexenylydenehydrazide d'acide benzene sulfonique
TL;DR: In this article, a 1,4-addltion reaction of methyl dithioacetate with alpha, β-disubstituted enones affords diastereomeric 5-oxodithioalkanoates, which are useful for selective synthesis of acyclic or semi-cyclic chains with 1, 2-adjacent asymmetric carbons.
TL;DR: Using an ester enolate Claisen rearrangement to prepare 1-carbomethoxy-2-(1′, 1′-dimethylallyl)-2, 3-dihydroindole-2-carboxylic acid followed by condensation with N-p-methoxybenzyl-glycyl-L-proline anhydride gave the title compound, a key intermediate in a synthetic approach to brevianamides A and B.
TL;DR: In this paper, the transposition of l'enolate de l'hydroxy-3 butyrate de butene-2yle donne l'(hydroxy -1' ethyl-2 methyl-3) pentene-4oate de methyle apres esterification au diazomethane
Abstract: La transposition de l'enolate de l'hydroxy-3 butyrate de butene-2yle donne l'(hydroxy-1' ethyl-2 methyl-3) pentene-4oate de methyle apres esterification au diazomethane
TL;DR: In this article, Wittig rearrangement to Ph(CH2CH)CHO and anionic Claisen rearrangements to (HO) deprotonated o-allylphenol were studied.
Abstract: The following systems have been studied: (i) the ion PhOPh2 on collisional activation undergoes Wittig rearrangement to Ph3CO– before fragmentation; (ii) PhOHCHCH2 undergoes competing rearrangements, viz. Wittig rearrangement to Ph(CH2CH)CHO– and anionic Claisen rearrangement to (HO) deprotonated o-allylphenol, with the former reaction predominating; (iii) deprotonation of dibenzyl ether yields an unstable species which forms PhCH2–: no Wittig rearrangement is observed in the gas phase although it occurs in the condensed phase; and (iv) PhCH2OCH2CHCH2 deprotonates to form the two interconvertible anions PhHOCH2CHCH2 and PhCH2OHCHCH2 of which the former is the more stable. Both ions give minor Wittig products, but the major process is loss of H2O to form a deprotonated dihydronaphthalene. There is some analogy between gas-phase and condensed-phase reactions in this system. The condensed-phase reaction of allyl benzyl ether under forcing conditions (lithium di-isopropylamide/tetrahydrofuran–hexamethylphosphoramide) gives the products 1-phenyl-but-3-en-1-ol, 1,2-dihydronaphthalene, and 1-(o-tolyl)prop-2-en-1-ol in the approximate ratio 4 : 3 : 1.
TL;DR: The sequence of a lactonic Claisen rearrangement and a Lewis acid catalyzed cyclocondensation of an aldehyde with an appropriate diene affords a new route to the title series as mentioned in this paper.
Abstract: The sequence of a lactonic Claisen rearrangement and a Lewis acid catalyzed cyclocondensation of an aldehyde with an appropriate diene affords a new route to the title series.
TL;DR: In this article, an intramolecular reaction of α-sulfenyl carbanion with epoxide was used to synthesize cubitene, a novel diterpene isolated from defense secretion of termites.
TL;DR: Claisen rearrangement of the acrylic esters 7 and 21 transferred the configuration of the cyclohexenols trans-2 and trans-17 to the aldehydes 11 and 23 as discussed by the authors.
Abstract: Durch Claisen-Umlagerung der Acrylsaureester 7 und 21 wird die Konfiguration der Cyclohexenole trans-2 und trans-17 auf die Aldehyde 11 und 23 ubertragen. Robinson-Anellierung fuhrt von dort zu den Titelverbindungen 15a und 27a. Die Aufbaufolge ist uber 14a, b iterativ angelegt. Zwei Ester des all-trans-Tercyclohexylalkohols 27a mit breiten smektischen Phasenbereichen werden beschrieben.
Aliphatic Liquid Crystals, 8. — Bi-and Tercyclohexyl Derivatives by Claisen Rearrangement
Claisen rearrangement of the acrylic esters 7 and 21 transfers the configuration of the cyclohexenols trans-2 and trans-17 to the aldehydes 11 and 23. Robinson annelation converts the latter to the title compounds 15a and 27a. The synthetic sequence is designed to be iterative via 14a, b. Two esters of the all-trans-tercyclohexyl alcohol 27a with broad smectic phase ranges are described.
TL;DR: In this article, a regioselective allylation of α-isocyanoesters at the α-carbon was achieved by the Claisen rearrangement of allylic α-IoS via the corresponding silyl ketene acetals in situ generated.