Showing papers on "Intramolecular reaction published in 1982"
TL;DR: In this paper, the reaction of NUC-allylpalladium complexes with carbon nucleophiles is a well-established reaction both stoichiometric and catalytic reactions are possible.
Abstract: Various transformations of allylic esters and ethers via ir—allylic complexes catalyzed by palladium—phosphine complexes have been studied Intramolecular reaction of a nucleophile offers a good synthetic method for five—membered ring ketones Also nucleophiles reacted easily with ct—acetoxy—,y—unsaturated nitriles and 1,3—diene monoepoxides It was found that the Carroll rearrangement is catalyzed by palladium complexes under mild conditions Facile formation of conjugated dienes and terminal olefins from allylic esters and ethers has been studied INTRODUCTION Palladium complexes catalyze numerous reactions (Refl) One important and unique group of reactions catalyzed by palladium complexes is the transformation of various allylic compounds Especially allylic ethers and esters undergo various reactions smoothly in the presence of palladium—phosphine complexes as a catalyst In the reaction of these allylic compounds, the first step is the oxidative addition of allylic compounds to Pd° species to form ir—allylpalladium complexes, which then undergo several transformations In this paper, several transformations of various allylic compounds catalyzed by palladium complexes discovered in our laboratory are presented REACTIONS OF NUCLEOPHILES The reaction of ¶-allylpalladium complexes with nucleophiles is a wellestablished reaction Both stoichiometric and catalytic reactions are possible (Ref2) Especially the reaction with carbon nucleophiles offers a good method for carbon—carbon bond formation We have studied further synthetic applications of reactions of allylic compounds via ir-allylpalladium complexes We have carried out studies aimed at preparing fiveand six-membered cyclic ketones by the palladium—catalyzed intramolecular reaction of active methylene with allyl phenyl ether moiety We have synthesized methyl (E)-3-oxo-8phenoxy-6-octenoate (1) by the reaction of the dianion of methyl acetoacetate with (E)-l-chloro-4-pfienoxy-2-butene (77% yield), and carried out its cyclization using 5-10 mol% of Pd(OAc)2-piosphine or phosphite as a catalyst in various solvents without using a base (Ref3) 0 CO2Me OPh 1 2Me eCO2Me + Pd(OAc)2 PPh3 2 —Pd(OAc)2 P T'°JCO2Me
110 citations
TL;DR: In this article, a series of carbene-chromium complexes bearing a phenyl substituent and an alkoxy-alkyne substitution have been prepared by acetoxy replacement.
37 citations
TL;DR: In this article, the authors used the conformational energy of the naphthalene unit to explain the small formation rate for rac-2,4-di(2-naphthyl)pentane.
Abstract: Intramolecular excimer formation processes were explained by the conformational energy calculated by an empirical method. Observed rate constants of excimer formation processes are closely correlated to the fraction of tg conformation. This indicates that intramolecular excimers are mainly formed by the internal rotation, trans→gauche, with reference to the naphthalene unit. The fraction of the tg conformation, which is an adjacent conformation to the excimer conformation on the conformational energy map, serves as an effective concentration of the intramolecular reaction. The small formation rate for rac-2,4-di(2-naphthyl)pentane is due to the unfavorable rotational mode (g+\ightleftarrowsg−) required to take the excimer conformation.
24 citations
TL;DR: In this article, a new synthetic method for macrolides based on intramolecular alkylation of dianions, generated from phenylthiomethyl group and protected cyanohydrin, is reported.
23 citations
14 citations
TL;DR: Rate and equilibrium constants were determined for anhydride formation from the thiol esters p-nitrophenyl thiosuccinate and N-acetyl-S-succinyl-beta-mercaptoethylamine and with enzyme-CoA, which support the anHydride mechanism for the enzymic reactions.
14 citations
TL;DR: In this paper, the structure of the benzofuran heterocycle was constructed by an intramolecular Wittig reaction of an o-bromomethylphenyl aroyl ester.
Abstract: The structure, 2-(2′,4′-dihydroxyphenyl)-5,6-methylenedioxybenzofuran (1), suggested for Sophora compound I has been confirmed by a synthesis in which the benzofuran heterocycle was constructed by an intramolecular Wittig reaction of an o-bromomethylphenyl aroyl ester. The congeneric Sophora compound II, 2-(2′-hydroxy-4′-methoxyphenyl)-5,6-methylenedioxybenzofuran (2) was synthesized by formation of the benzofuran via the reaction of a copper(I) arylacetylide with an o-iodophenyl ester.
12 citations
TL;DR: Support is provided for a mechanism that proceeds through an anhydride intermediate in the enzymic reaction catalyzed by CoA transferase, which can be made rapid and favorable by making the reacting groups intramolecular; and catalyzing the expulsion of the leaving group.
8 citations
TL;DR: In this article, the effect of the polymeric structure of the catalyst and of formal-dehyde on the condensation reaction is accounted for by an intramolecular reaction mechanims.
5 citations
TL;DR: The first proved example of methyl transfer by an endocyclic nucleophilic substitution was given in this paper, where the amino-ester was converted into the betaine by an intramolecular methyl transfer.
Abstract: Conversion of the amino-ester (6) into the betaine (7) proceeds at low concentrations partly by way of an intramolecular methyl transfer, whereas the corresponding reaction of the lower homologue (4) is entirely intermolecular; the intramolecular reaction is the first proved example of methyl transfer by an endocyclic nucleophilic substitution.
5 citations
TL;DR: In this paper, several transformations of various allylic compounds catalyzed by palladium complexes discovered in our laboratory are presented, including the formation of conjugated dienes and terminal olefins from allylic esters and ethers.
Abstract: Various transformations of allylic esters and ethers via ir—allylic complexes catalyzed by palladium—phosphine complexes have been studied. Intramolecular reaction of a nucleophile offers a good synthetic method for five—membered ring ketones. Also nucleophiles reacted easily with ct—acetoxy—,y—unsaturated nitriles and 1,3—diene monoepoxides. It was found that the Carroll rearrangement is catalyzed by palladium complexes under mild conditions. Facile formation of conjugated dienes and terminal olefins from allylic esters and ethers has been studied. INTRODUCTION Palladium complexes catalyze numerous reactions (Ref.l). One important and unique group of reactions catalyzed by palladium complexes is the transformation of various allylic compounds. Especially allylic ethers and esters undergo various reactions smoothly in the presence of palladium—phosphine complexes as a catalyst. In the reaction of these allylic compounds, the first step is the oxidative addition of allylic compounds to Pd° species to form ir—allylpalladium complexes, which then undergo several transformations. In this paper, several transformations of various allylic compounds catalyzed by palladium complexes discovered in our laboratory are presented. REACTIONS OF NUCLEOPHILES The reaction of ¶-allylpalladium complexes with nucleophiles is a wellestablished reaction. Both stoichiometric and catalytic reactions are possible (Ref.2). Especially the reaction with carbon nucleophiles offers a good method for carbon—carbon bond formation. We have studied further synthetic applications of reactions of allylic compounds via ir-allylpalladium complexes. We have carried out studies aimed at preparing fiveand six-membered cyclic ketones by the palladium—catalyzed intramolecular reaction of active methylene with allyl phenyl ether moiety. We have synthesized methyl (E)-3-oxo-8phenoxy-6-octenoate (1) by the reaction of the dianion of methyl acetoacetate with (E)-l-chloro-4-pfienoxy-2-butene (77% yield), and carried out its cyclization using 5-10 mol% of Pd(OAc)2-piosphine or phosphite as a catalyst in various solvents without using a base (Ref.3). 0 CO2Me OPh 1 2Me eCO2Me + Pd(OAc)2 PPh3 2 —Pd(OAc)2 P T'°JCO2Me