• Li G, Gu Y, Ding Y, Yong Z, Hanpeng W, Jianming G, Qiang Y, Liang SL (2004) Wells-Dawson type molybdovanadophosphoric heteropolyacids catalyzed Prins cyclization of alkenes with paraformaldehyde under mild conditions-a facile and efficient method to 1,3-dioxane derivatives. (springer.com)
  • Yadav JS, Reddy BVS, Kumar NGGKS, Aravind S (2008) The 'aqueous' Prins cyclization: a diastereoselective synthesis of 4-hydroxytetrahydropyran derivatives. (springer.com)
  • One-pot tandem Meyer-Schuster rearrangement of arylpropynols and successive radical cyclization with disulfides enables the synthesis of 2-sulfenylindenone derivatives in good yields. (organic-chemistry.org)
  • A nitrogen-containing Lewis base mediated regioselective [4 + cyclization strategy between allenic esters and α,β-unsaturated ketimines was discovered, affording a series of hydropyridine derivatives in moderate to good yields under mild conditions. (rsc.org)
  • Cross-cyclization with phthalonitrile or diiminoisoindole derivatives is possible introducing a flexibile synthetic route that has led to the synthesis of porphyrazines with peripheral heterocyclic rings, heteroatom substituents (S, O, N), peripherally bound metal atoms, and mixed -benzo porphyrazine systems. (wikipedia.org)
  • These reagents, as well as other, more exotic adducts of nitrogen heterocycles with chromium(VI), facilitate a number of oxidative transformations of organic compounds, including cyclization to form tetrahydrofuran derivatives and allylic transposition to afford enones from allylic alcohols. (wikipedia.org)
  • Under UV irradiation, stilbene and its derivatives undergo intramolecular cyclization to form dihydrophenanthrenes. (wikipedia.org)
  • A novel palladium( II ) catalysed tandem cyclisation of substituted 2-alkenylphenyl alkynones gives substituted 2-vinyl indenones and 6,5,6-fused tricyclic lactone skeletons (pyrones), in one-pot. (rsc.org)
  • The unprecedented combination of a palladium( II ) complex with a chiral Bu-QUOX ligand and a chiral phosphoric acid enables the highly efficient asymmetric oxidative tandem cyclization of N -(2,2-disubstituted hex-5-en-1-yl)acrylamides, providing a straightforward method to access chiral 6,5-bicyclic aza-heterocycles in moderate to good yields and with excellent enantioselectivities. (rsc.org)
  • The first example of the palladium-catalyzed tandem addition/cyclization of 2-(2-acylphenoxy)acetonitriles with arylboronic acids has been developed, providing a new strategy for the synthesis of 2-aroyl benzofurans with excellent chemoselectivity and wide functional group compatibility. (rsc.org)
  • Preliminary mechanistic experiments indicate that this tandem process involves sequential nucleophilic addition generating 2-(2-acylphenoxy)-1-phenylethan-1-one followed by an intramolecular cyclization. (rsc.org)
  • The first ratiometric fluorescent probe for the detection of a nerve agent simulant was developed based on tandem phosphorylation and intramolecular cyclization, by which high sensitivity as well as large emission shift could be achieved. (rsc.org)
  • A novel and efficient strategy for the synthesis of 4-chloro quinolines via the TMSCl-mediated cascade cyclization of easily prepared ortho -propynol phenyl azides is developed. (rsc.org)
  • The compounds [3-(2-Bromocyclohex-2-enyloxy)prop-1-ynyl]- tert -butyl-dimethylsilane 3 , [4-(2-bromocyclohex-2-en-1-yloxy)but-2-yn-1-yloxy]tert-butyldimethylsilane 5 and dimethyl 2-(2-bromocyclohex-2-enyl)-2-(3-( tert -butyldimethylsilanyl)prop-2-ynyl)malonate 9 were prepared and subjected to palladium-catalyzed intra-intermolecular cascade cross couplings incorporating bicyclopropylidene 10 under two types of conditions. (mdpi.com)
  • Two major routes for the synthesis of 2-bromo-1,6-enynes as precursors for palladium-catalyzed cascade cyclizations have previously been developed [ 32 ]. (mdpi.com)
  • The cascade radical cyclization-ring-opening-anionic cyclization allowed facile and efficient access to 2-(2-hydroxyalkyl)cyclopropanols from readily available materials. (rsc.org)
  • The development of a method for performing radical initiated intramolecular cascade cyclization of 1, n -enynes provided a competent protocol for producing structurally diverse complex heterocycles. (rsc.org)
  • The cascade cyclization leads to an increase in molecular complexity to furnish naphtho[1,2-d]triazoles in satisfactory yields. (biomedsearch.com)
  • An antibody has been induced that efficiently catalyzes a cationic cyclization in which an acyclic olefinic sulfonate ester substrate is converted almost exclusively (98 percent) to a cyclic alcohol. (sciencemag.org)
  • New catalysts for cationic cyclization may be of general use in the formation of carbon-carbon and carbon-heteroatom bonds leading to multi-ring molecules including steroids and heterocyclic compounds. (sciencemag.org)
  • Cationic cyclization of ketene dithioacetals. (wikipedia.org)
  • The most common and synthetically useful strategy couples the cationic 2-aza-Cope rearrangement with a Mannich cyclization, and is the subject of much of this article. (wikipedia.org)
  • However, when considering the atom economy it as to be mentioned that the Pschorr cyclization has often only low yields. (wikipedia.org)
  • A copper/iodine cocatalyzed decarboxylative cyclization of α-amino acids with either 2-benzoylpyridines or 2-benzoylquinolines provides 1,3-disubstituted imidazo[1,5- a ]pyridines and 1,3-disubstituted imidazo[1,5- a ]quinolines in excellent yields. (organic-chemistry.org)
  • An efficient palladium-catalyzed intramolecular cyclization of 2-iodobenzamides with a 2-oxoethyl function group on the nitrogen atom moiety provides 3-acyl isoindolin-1-ones and 3-hydroxy-3-acylisoindolin-1-ones under mild conditions in good yields. (organic-chemistry.org)
  • It is important to note that the Au(I)-catalyzed cyclization proceeds in high yields in a sterically congested environment. (beilstein-journals.org)
  • However, one might recognize that the low chemical yields encountered in some steps undermine the efficacy of the Au(I)-catalyzed cyclization approach. (beilstein-journals.org)
  • Cyclization of the resultant β-ketoacid yields a tricyclic ketone. (wikipedia.org)
  • while in Mechanism II, the elimination yields the nitrilium intermediate prior to cyclization. (wikipedia.org)
  • Stereochemistry In order to determine, whether the replacement of hydrogen in the cyclization of N-haloamines proceeds with retention, inversion, or equilibration of configuration, deuterated amine 9 was synthesized. (wikipedia.org)
  • Enantioselective construction of multifunctionalized spirocyclohexaneoxindoles through organocatalytic Michael-Aldol cyclization of isatin derived alkenes with linear dialdehydes. (sigmaaldrich.com)
  • The radical cyclization between aliphatic acyclic esters and alkenes was achieved unprecedentedly in the presence of allylsamarium bromide with HMPA and H 2 O as additives. (rsc.org)
  • This study demonstrates that mild non-enzymatic conditions are sufficient for the cyclization of creatine ethyl ester into creatinine, and together with previous results obtained under enzymatic conditions suggests that there are no physiological conditions that would result in the production of creatine. (nih.gov)
  • InBr3-Catalyzed Cyclization of Glycals with Aryl Amines. (docme.ru)
  • Glycal Cyclization InBr3-Catalyzed Cyclization of Glycals with Aryl Amines** Jhillu S. Yadav,* Basi V. S. Reddy, Katta V. Rao, Kavuda Saritha Raj, Atlaluri R. Prasad, Singarapu Kiran Kumar, Ajit C. Kunwar, Panjula Jayaprakash, and Bulusu Jagannath Scheme 1. (docme.ru)
  • As reported in Nature Chemistry, scientists from IBM Research and CiQUS at the University of Santiago de Compostela, demonstrated a reversible Bergman cyclisation for the first time using an atomic force microscope. (wikipedia.org)
  • There is compelling experimental and theoretical evidence for formation of nondirect sequence ions via cyclization/reopening chemistry in the CID spectra of the b tons when the His residue is near the C-terminus. (springer.com)
  • 8 Despite these significant advances, to the best of our knowledge, catalytic sulfonyl-radical triggered 1,5-enyne-cyclization for the regiospecific construction of unsymmetrical diaryl sulfones has not yet been documented ( Scheme 1 , route viii). (rsc.org)
  • Moreover, catalytic 1,5-enyne-cyclizations have become an important platform for the collection of complicated hetero-and carbocycles. (rsc.org)
  • Herein, we would like to report this new catalytic sulfonyl radical-triggered unactivated 1,5-enyne-cyclization, leading to the regiospecific formation of unsymmetrical diaryl sulfones 4 ( Scheme 2d ). (rsc.org)
  • Methyl vinyl ketone and acetoacetic ester undergo aldol cyclization in the presence of catalytic pyrrolidinum acetate or Triton B or sodium ethoxide to produce Hagemann's ester. (wikipedia.org)
  • The ene cyclization has evolved to become an indispensable tool for the synthesis of various ring size heterocyclic compounds. (rsc.org)
  • Moreover, the ease of regio- and stereoselectivity of ene cyclization has led to the development of new types of heterocyclic compounds. (rsc.org)
  • An efficient CuI-catalyzed coupling cyclization of gem -difluoroalkenes with active methylene carbonyl compounds such as 1,3-dicarbonyl compounds, acetoacetonitrile, and phenylsulfonylacetone enables the synthesis of 2,3,5-trisubstituted furans with the assistance of a base. (organic-chemistry.org)
  • Many of these compounds are capable of undergoing Bergman cyclization. (wikipedia.org)
  • Computational studies have been performed on potassium alkoxide-allenes, as well as potassium and lithium amido-allenes to probe the mechanism of their cyclizations to dihydrofurans and to 2,5-dihydropyrroles. (strath.ac.uk)
  • The mechanism for this cyclization is not yet understood. (wikipedia.org)
  • However, low concentrations of a radical scavenger establish thermodynamic control and provide access to 6-endo products-not via 6-endo cyclization, but by 5-exo cyclization followed by 3-exo closure and subsequent fragmentation (Dowd-Beckwith rearrangement). (wikipedia.org)
  • This indicates less active cyclization/reopening followed by fragmentation of common structures for b n ions containing His than for sequences of solely aliphatic residues. (springer.com)
  • Despite more energetically favorable cyclization barriers for the b 5 structures, the b 4 ions experimental data show more clear evidence of cyclization and sequence scrambling before fragmentation. (springer.com)
  • A unique protocol for the synthesis of substituted and fused pyrroles has been developed through the iridium catalyzed fragmentation/cyclization of related N -butynyl 4,4-dimethylisoxazolidine-3,5-diones in hot ethanol. (rsc.org)
  • Prins cyclization of isoprenol with benzaldehyde as a model aldehyde was performed using montmorillonite K10 as an acid catalyst. (springer.com)
  • More GP, Rane M, Bhat SV (2012) Efficient Prins cyclization in environmentally benign method using ion exchange resin catalyst. (springer.com)
  • Ruthenium tetroxide (1 mol%) has been used as a catalyst for the oxidative mono-cyclization of 1,5,9-trienes and polyenes . (rsc.org)
  • In 1994, Prof. Isamu Shiina (Tokyo University of Science, Japan) reported an acidic cyclization method using Lewis acid catalyst, and, in 2002, a basic cyclization using nucleophilic catalyst. (wikipedia.org)
  • On the final module is the TE domain used as a catalyst for cyclization or product release. (wikipedia.org)
  • Using 2-arylalkynyl-1,1′-biphenyls as a replacement for 1,5-enynes, this transformation could also proceed smoothly, enabling sulfonyl radical-triggered 6- endo-trig cyclization and homolytic aromatic substitution (HAS) to deliver unsymmetrical diaryl sulfones 6 with different substitution patterns ( Scheme 2e ). (rsc.org)
  • Scheme 2 Sulfonyl radical-triggered cyclization. (rsc.org)
  • Although the cyclization of enol ether 5 can produce 5- exo and 6- endo products, we found that gold complexes 6 , having bulky phosphine ligands such as 2-bis( tert -butylphosphino)biphenyl, gave exclusively the 6- endo-dig cyclized products 7 ( Scheme 1 ). (beilstein-journals.org)
  • In the course of our studies directed towards the synthesis of naturally occurring PPAPs and related carbon-bridged ketone scaffolds, we envisioned that PPAP framework 1 could be generated via a Au(I)-catalyzed cyclization [14-. (beilstein-journals.org)
  • The monoxides of a number of 1,5-dienes were prepared and treated with a variety of acidic reagents known to induce cyclization of the parent diolefins. (caltech.edu)
  • This precursor is treated with base to induce cyclization. (wikipedia.org)
  • Bio-inspired acetal induced polyene cyclization : the development and applications. (ntu.edu.sg)
  • The development of a bio-inspired acetal induced intermolecular polyene cyclization is described. (ntu.edu.sg)
  • By exploiting the acetal induced intermolecular polyene cyclization, a highly efficient method to construct 8-oxabicyclo[3,2,ctanes was discovered. (ntu.edu.sg)
  • A novel method for the preparation of 2,3-dihydroimidazo[2,1-b]thiazole 9 by iodination and subsequent cyclization of the easily available N-allylimidazoline-2-thiones 5, is described. (uzh.ch)
  • CLIPS (Chemical Linkage of Peptides onto Scaffolds) Cyclization is an integrated technology that combines chemical linkage of a linear peptide to a synthetic scaffold with conformational fixation of the peptide. (creative-peptides.com)
  • As a technology for peptide cyclization, the CLIPS TM (Chemically Linked Peptides on Scaffolds) has been applied successfully in identifying the epitope on human CD20 and reconstructing the conformational epitope on follicle stimulating hormone. (creative-peptides.com)
  • Rapid and quantitative cyclization of multiple peptide loops onto synthetic scaffolds for structural mimicry of protein surfaces. (creative-peptides.com)
  • The cyclization of the peptide around a metal core was shown to greatly increase the affinity of the peptide for its target. (umsystem.edu)
  • The primary problem with the cyclization of the peptide is the fact that two main products are produced. (umsystem.edu)
  • Breugst M, Grée R, Houk KN (2013) Synergistic effects between Lewis and Brønsted acids: application to the Prins cyclization. (springer.com)
  • Borkar P, Weghe P, Reddy BVS, Yadav JS, Grée R (2012) Unprecedented synergistic effects between weak Lewis and Brønsted acids in Prins cyclization. (springer.com)
  • Yheng K, Liu X, Qin S, Xie M, Lin M, Hu C, Feng X (2012) Completely OH-selective FeCl3-catalyzed Prins cyclization: highly stereoselective synthesis of 4-OH-tetrahydropyrans. (springer.com)
  • Yadav JS, Reddy BVS, Chaya DN, Kumar NGGK, Naresh P, Jagadeesh B (2009) Heteropoly acid-catalyzed aza-Prins-cyclization: an expeditious synthesis of 4-hydroxypiperidines. (springer.com)
  • Similarly, β-substitution directed inward restricts the s-trans conformation so severely that E-Z isomerization has been shown to occur in advance of cyclization on a wide range of substrates, yielding the trans cyclopentenone regardless of initial configuration. (wikipedia.org)
  • The poly-unsaturated substrates underwent mono-cyclization with a high degree of diastereo- and positionselectivity to produce mono-tetrahydrofuran diols with a varying degree of unsaturation. (rsc.org)
  • In contrast, cyclizations of deuterium-labeled carboxylic acid substrates undergo anti oxypalladation. (caltech.edu)
  • The hydroxyl group in the seco acid attacks its host molecule through intramolecular nucleophilic substitution, and at the same time, carboxylate anion, derived from 2-methyl-6-nitrobenzoic acid, acts as a deprotonation agent, promoting the progression of the cyclization and producing the desired lactone. (wikipedia.org)
  • Alkynoic acids derived from salicylic acid and analogues undergo arylative cyclization with arenediazonium salts promoted by gold in the absence of external ligands. (rsc.org)
  • Instead of the cyclization to the expected nine-membered cyclodepsipeptide, only the chloro acid 12 was obtained. (uzh.ch)
  • When cyclization was induced in deuterated acid, the trans, trans-diene gave 2^t, 3^c-dlmethyl-4-deuterocyclohexyl^c formate, while the cis, cis-isomer produced the C-4 epimer. (caltech.edu)
  • Instead of catalyzing the Pictet-Spengler cyclization with strong acid, one can acylate the iminium ion forming the intermediate N-acyliminium ion. (wikipedia.org)
  • He also elucidated the mechanistic pathways of the transformations and developed methodologies for benzyne cyclisation of anils and Lewis acid- promoted lithiation, both have since become standard synthetic procedures. (wikipedia.org)
  • Simultaneously, residual aromatic carboxylic acid salt, which is derived from the MA, acts as a deprotonation agent, causing the cyclization to progress and produce the desired lactone. (wikipedia.org)
  • The resulting o-benzoylbenzoic acid then undergoes cyclization, forming anthraquinone. (wikipedia.org)
  • Radical-radical cyclisation cascades, triggered by single-electron-transfer to amide-type carbonyls using SmI 2 -H 2 O-LiBr, result in the selective construction of quaternary carbon stereocentres. (rsc.org)
  • The first example of versatile synthesis of functionalized β-carbolines and γ-carbolines via redox-free Pd-catalyzed C-H addition of indole to nitrile/cyclization sequences is reported. (rsc.org)
  • To realize the strategy shown in Figure 3 , cis -bicyclo[3.3.ctane-3,7-dione ( 1 ) [44-was subjected to twofold Fischer indole cyclization to generate the diindole derivative 6 by using 1-methy-1-phenylhydrazine ( 5 ) under HCl/EtOH reflux conditions. (beilstein-journals.org)
  • The primary peroxide adducts subsequently undergo intramolecular Diels-Alder (IMDA) cyclization, affording a number of diastereomeric tricyclic adducts that have characteristic carbonyl (13)C chemical shifts at ~198 ppm. (sigmaaldrich.com)
  • The energy profiles for 4-exo-trig cyclizations onto the allenes are also explored, and the preferred formation of the observed five-membered products is rationalized. (strath.ac.uk)
  • In many cases, exo cyclization is favored over endo cyclization (macrocyclizations constitute the major exception to this rule). (wikipedia.org)
  • Although the exo radical is less thermodynamically stable than the endo radical, the more rapid exo cyclization is rationalized by better orbital overlap in the chair-like exo transition state (see below). (wikipedia.org)
  • Stabilizing the initially formed radical with electron-withdrawing groups provides access to more stable 6-endo cyclization products preferentially. (wikipedia.org)
  • Herein, we demonstrate I 2 /TBHP promoted, solvent controlled, regio- and chemoselective 5- exo -trig or 6- endo -trig radical cyclization of electronically unbiased 1, n -enynes to synthesize nitrogen-containing heterocycles. (rsc.org)
  • A long-standing proposal envisaged electron transfer from dimsyl anions (formed by deprotonation of the solvent DMSO) but this pathway shows an exceptionally high kinetic barrier, while direct 5-endo-trig cyclization of the alkoxides and amides is much more easily achievable. (strath.ac.uk)
  • Gold(I)-catalyzed 6- endo-dig cyclization. (beilstein-journals.org)
  • 7) Endo cyclization is observed most often when small or large rings are involved. (wikipedia.org)
  • For instance, 5-endo cyclization is generally preferred over 4-exo cyclization. (wikipedia.org)
  • 5-endo-dig cyclization (see: Baldwin's rules). (wikipedia.org)
  • It was found that mild aqueous conditions result in the cyclization of creatine ethyl ester to provide inactive creatinine as the exclusive product, and this transformation becomes nearly instantaneous as the pH approaches 7.4. (nih.gov)
  • 10 Thus far, two main 1,5-enyne-cyclization strategies involving metal catalysis 11 or electrophilic cyclization 12 have been developed. (rsc.org)
  • We assume, in line with previous results , that cyclisation occurs only after the addition of the electrophilic trap (which, precedent suggests, attacks the pyridine lone pair and activates the ring as an acylpyridinium species even in the presence of the lithium enolate). (beilstein-journals.org)