Showing papers on "Intramolecular reaction published in 1986"
TL;DR: The field of intramolecular reactions is a mature area in which the merging of concepts from both physical organic chemistry and polymer chemistry leads to a unified treatment of cyclization rates and equilibria in terms of a few simple generalizations and theories as discussed by the authors.
Abstract: Publisher Summary This chapter focuses that the field of intramolecular reactions is a mature area in which the merging of concepts from both physical organic chemistry and polymer chemistry leads to a unified treatment of cyclization rates and equilibria in terms of a few simple generalizations and theories. It is concerned with reaction rates, equilibria, and mechanisms of cyclization reactions of chain molecules. It discusses that parallel to the search for synthetic methods to make rings of all sizes, kinetic studies have appeared with the aim of providing insight into physical aspects of ring closure. A significant portion of the evidence available on the kinetics of intramolecular reactions falls in the domain of neighboring group participation. The term is sufficiently wide to encompass “all intramolecular reactions and all reactions that involve nonelectrostatic through-space interactions between groups in the same molecule.” However, the most common types of neighboring group participation involve nucleophilic participation either with or without anchimeric assistance and intramolecular acid and base catalysis. The chapter explores that intramolecular catalysis phenomena have attracted much attention, both from the experimental and theoretical points of view, not only on account of their inherent mechanistic interest, but also because they are believed to model the extraordinary efficiency of enzyme catalysis.
179 citations
132 citations
TL;DR: The X-ray structural information for both 1 and 2 is consistent with a cyano rather than an isocyano arrangement,1° and this is confirmed by the infrared spectra.
Abstract: 31.30; H, 5.22; N, 36.52. Found: C, 31.34; H, 5.25; N, 36.70. Low-resolution mass spectral analysis showed the expected molecular ion at m / e 345. The infrared spectrum contained a cyano stretching peak at 2180 cm-'. The 31P NMR spectrum consisted of a singlet at -7.8 ppm. Crystals suitable for X-ray analysis were grown by slow evaporation of a solution of 2 in hexane. The structure of 2 is illustrated in Figure 2, and important structural parameters are given in Table I.9 Both compounds, 1 and 2, are stable in contact with the atmosphere and are unaffected when heated to moderate temperatures. The X-ray structural information for both 1 and 2 is consistent with a cyano rather than an isocyano arrangement,1° and this is confirmed by the infrared spectra.\" The triple bonds of the cyano groups in 2 are slightly longer than that in 1, but no evidence could Figure 2. ORTEP representation of the structure of non-gem-trans-tris(dimethy1amino)tricyanocyclotriphosphazene (2).
111 citations
TL;DR: Diketopiperazine formation rates under the usual conditions of a solid phase peptide synthesis cycle with Fmoc-amino acids have been studied on a p -alkoxybenzyl ester resin.
104 citations
TL;DR: The stepwise AdE-reaction of dicobalt hexacarbonyl complexes of conjugated enynes has been extended to include unsaturated electrophiles and nucleophiles to produce products with an orientation conducive to a subsequent conversion into polycyclic compounds via an intramolecular Khand-Pauson type reaction as discussed by the authors.
89 citations
88 citations
TL;DR: In this article, reactions d'halogenures d'acide benzeneseleninique avec des N-[alcene-4-and -5yl] acetamides ou des butene-3yl-4 pyrrolidone-2 and -azetidinone-6 carbapename
Abstract: Reactions d'halogenures d'acide benzeneseleninique avec des N-[alcene-4- et -5yl] acetamides ou des butene-3yl-4 pyrrolidone-2 et -azetidinone-2: synthese de phenylselenomethyl-2 pyrrolidines et phenylseleno-3- et phenylselenomethyl-2 piperidines N-acetylees, de phenylselenomethyl-3 pyrrolizidine et de phenylselenomethyl-3 isopropyl-6 carbapename
75 citations
TL;DR: Etude de la cyclisation radicalaire par reaction de (BU) 3 SnH des R-8 iodo-2' ethyl-7 methoxy-6 vinyl-8 perhydro pyranno [3,2d] m-dioxinnes as discussed by the authors.
Abstract: Etude de la cyclisation radicalaire par reaction de (BU) 3 SnH des R-8 iodo-2' ethyl-7 methoxy-6 vinyl-8 perhydro pyranno [3,2-d] m-dioxinnes (R=formylmethyl, cyanomethyl, propargyl): obtention de perhydro pentaleno [6a',1'-4,5] pyranno [3,2-d] m-dioxinnes
71 citations
69 citations
TL;DR: In this article, the radical cationique derive de l'adamantyl-2]-9 aza-9 bicyclo [3.3.1] nonane is discussed.
Abstract: Deprotonation du radical cationique derive de l'[adamantyl-2]-9 aza-9 bicyclo [3.3.1] nonane
66 citations
TL;DR: In this paper, the authors discuss the effect of attention d'isoxazoles et al. on pyrolyse, peuvent donner des pyrroles.
Abstract: Obtention d'isoxazoles et d'isoxazoles condenses qui, par pyrolyse, peuvent donner des pyrroles. Mecanismes
TL;DR: In this article, α-Alkylidene-γ-lactones are obtained by treatment of chloroformate and selenocarbonate derivatives of homopropargylic alcohols with tri-n-butylstannane.
TL;DR: In this paper, the authors introduce the introduction of lasymetrie par scission regioselective d'un oxiranne methanol and formation of cycle a 14 carbones utilisant les conditions de la reaction de Horner Emmons.
Abstract: Synthese enantioselective avec comme etapes cles: l'introduction de l'asymetrie par scission regioselective d'un oxiranne methanol et formation d'un cycle a 14 carbones utilisant les conditions de la reaction de Horner Emmons developpees par Masamune et Ronsh
TL;DR: In this paper, the condensation of immonium ions with allylsilanes in aqueous tetrahydrofuran at ambient temperature gives rise to five, six, seven, and eight-membered rings containing nitrogen.
TL;DR: In this paper, an approach to the regio-controlled synthesis of 1,2- and/or 1,3-diols was proposed. But this approach was not suitable for allyl and homoallyl alcohols and the subsequent oxidative cleavage of the resultant carbon-silicon bond.
TL;DR: In the presence of SnCl 4 de nitro-1 nonadiene-1,7 and n-oxide-2 decadiene -2,8: obtention d'oxydes-3 dhexahydro-4a,5,6,7,8,8-8, 8a benzooxazines-2,3 as mentioned in this paper.
Abstract: Cycloadditions stereoselectives intramoleculaires en presence de SnCl 4 de nitro-1 nonadiene-1,7 et de nitro-2 decadiene-2,8: obtention d'oxydes-3 d'hexahydro-4a,5,6,7,8,8a benzooxazines-2,3
TL;DR: In this paper, the temporary incorporation of a coordinating phosphine residue [m -(Ph 2 P)C 6 H 4 CO] into the tetracyclic phyllanthocin precursor 1a directed the [(COD)RhOAc] 2 -catalyzed hydroformylation of 1d largely to the desired C(3) position.
TL;DR: Construction d'un cyclopenta [a] pentalene carboxylate-3 d'ethyle precurseur de la corioline as discussed by the authors, a cyclopentina is constructed by the construction of cyclopenia.
Abstract: Construction d'un cyclopenta [a] pentalene carboxylate-3 d'ethyle precurseur de la corioline
TL;DR: Starting from (S)-3-methyl-1-penten-5-o1 3a enantiomerically pure (+)-α-skytanthine 9, (+)-δ-skyTanthine 11 and (+)-iridomyrmecin 12 were synthesized via the magnesium-ene reaction.
TL;DR: Anatoxin-a has been synthesized in 8 steps, starting from succinimide, 4-bromo-1-butene and dimethyl (2-oxopropyl)phosphonate, by employing as the key step an intramolecular reaction of an N-acyliminium precursor with an α,β-unsaturated ketone moiety, induced by saturated HCl in MeOH at −50°C as discussed by the authors.
TL;DR: Etude du transfert du groupe acyl de S-[acyloxy-6 dibenzofuryl-4thio] cysteines sur l'azote de la cysteine (acyl=acetoxy ou alanyl N-protege) as mentioned in this paper.
Abstract: Etude du transfert du groupe acyl de S-[acyloxy-6 dibenzofuryl-4thio] cysteines sur l'azote de la cysteine (acyl=acetoxy ou alanyl N-protege)
TL;DR: Synthese du compose du titre (methyl-1 perhydro methano-2,5 quinoleine) via une addition intramoleculaire de Diels Alder du cation iminium obtenu a partir de methylamine and de cyclohexadiene-2.4 butanal as mentioned in this paper.
Abstract: Synthese du compose du titre (methyl-1 perhydro methano-2,5 quinoleine) via une addition intramoleculaire de Diels Alder du cation iminium obtenu a partir de methylamine et de cyclohexadiene-2,4 butanal
TL;DR: In this article, a reaction intramoleculaire de Diels Alder de l'acetyl-4 N-[t-butyldimethylsiloxy-5 pentyne-3yl] is described.
Abstract: Synthese d'acetyl-6 hydroxy-5 methoxy-4 tetrahydro-3,6,7,8 benzo [1,2-b:4,3-b'] dipyrrolecarboxylate-2 de methyle (ester de methyle de PDE II) a partir du dimethylacetal de l'acetylcetene et du tetrazine-1,2,4,5 dicarboxylate-3,6 de dimethyle (addition de Diels Alder avec demande d'electron inverse) et par l'intermediaire d'une reaction intramoleculaire de Diels Alder de l'acetyl-4 N-[t-butyldimethylsiloxy-5 pentyne-3yl] acetamido-3 methoxy-5 pyridazine
TL;DR: La reduction electrochimique de derives de l'aryl-5 pentanone-2 conduit a des derives of l'hexahydro-1,2,3,4,6,8a methyl-1) naphtol-1 as discussed by the authors.
Abstract: La reduction electrochimique de derives de l'aryl-5 pentanone-2 conduit a des derives de l'(hexahydro-1,2,3,4,6,8a methyl-1) naphtol-1