scholarly journals Observation of a Tricyclic[4.1.0.02,4]heptane During a Michael Addition-Ring Closure Reaction and a Computational Study on Its Mechanism of Formation

2017 ◽  
Vol 82 (23) ◽  
pp. 12511-12519 ◽  
Author(s):  
Marco Farren-Dai ◽  
John R. Thompson ◽  
Anna Bernardi ◽  
Cinzia Colombo ◽  
Andrew J. Bennet
Keyword(s):  
Michael Addition ◽  
Computational Study ◽  
Ring Closure ◽  
Mechanism Of Formation

A new heterocyclic ring closure in ferricyanide oxidation of 2,4,6-triphenylpyridinium salts

1983 ◽  
Vol 48 (11) ◽  
pp. 3307-3314 ◽  
Author(s):  
Petr Nesvadba ◽  
Petr Štrop ◽  
Josef Kuthan
Keyword(s):  
Alkaline Solution ◽  
Heterocyclic Ring ◽  
Potassium Ferricyanide ◽  
Probable Mechanism ◽  
Ring Closure ◽  
Pyridinium Salts ◽  
Mechanism Of Formation ◽  
Pyrrole Derivatives ◽  
Quaternary Pyridinium Salts ◽  
Heterocyclic Derivatives

The quaternary pyridinium salts Ia-Ic react with alkaline solution of potassium ferricyanide to give the condensed heterocyclic derivatives IIIa, b, IV, whereas the salts Id-If give the pyrrole derivatives IIa-IIc under the same conditions. The diaza heterocycle IIIa reacts with methyl iodide to give methoiodide V, whereas by action of bromine it produces two monobromo derivatives VIa, b. The pyrrole derivatives IIa, b give monobromo derivatives IId, e on bromination. A probable mechanism of formation of the heterocyclic derivatives is discussed.

Catalyst-Free One-Pot Synthesis of Novel Heteroarylamine Substituted Furo[3,2-c]coumarins

Synlett ◽  
2018 ◽  
Vol 29 (12) ◽  
pp. 1589-1592 ◽  
Author(s):  
Abolfazl Olyaei ◽  
Mahnaz Saraei ◽  
Reyhaneh Khoeiniha
Keyword(s):  
Michael Addition ◽  
Aldol Condensation ◽  
Ring Closure ◽  
Dehydration Reaction ◽  
One Pot ◽  
Catalyst Free ◽  
One Pot Synthesis ◽  
Tandem Process ◽  
First Time

A high-yielding cyclocondensation of 4-hydroxycoumarin, phenylglyoxal monohydrate, and heteroarylamines proceeds without catalysis, which gives novel functionalized furo[3,2-c]coumarins and heteroarylamino alkylation of coumarin products in acetonitrile under reflux, is reported for the first time. This tandem process involves sequentially an aldol condensation, Michael addition, a ring closure, and dehydration reaction.

scholarly journals A computational study of the influence of methyl substituents on competitive ring closure to α- and β-lactones

2017 ◽  
Vol 15 (34) ◽  
pp. 7235-7240 ◽  
Author(s):  
Philippe B. Wilson ◽  
Ian H. Williams
Keyword(s):  
Computational Study ◽  
Ring Closure

gem-Dimethyl substitution at C3 enhances the preference for β-lactone formation from 2-chlorosuccinate but methylation at C2 almost favours α-lactone.

A Highly Efficient Synthesis of Lamellarins K and L by the Michael Addition/Ring-Closure Reaction of Benzyldihydroisoquinoline Derivatives with Ethoxycarbonyl-β-nitrostyrenes

2004 ◽  
Vol 116 (7) ◽  
pp. 884-886 ◽  
Author(s):  
Poonsakdi Ploypradith ◽  
Chulabhorn Mahidol ◽  
Poolsak Sahakitpichan ◽  
Siriporn Wongbundit ◽  
Somsak Ruchirawat
Keyword(s):  
Michael Addition ◽  
Ring Closure ◽  
Efficient Synthesis ◽  
Highly Efficient ◽  
The Michael Addition

Trapping acrylamide by a Michael addition: A computational study of the reaction between acrylamide and niacin

2014 ◽  
Vol 114 (9) ◽  
pp. 553-559 ◽  
Author(s):  
George Papamokos ◽  
Jens Dreyer ◽  
Luciano Navarini ◽  
Paolo Carloni
Keyword(s):  
Michael Addition ◽  
Computational Study

scholarly journals Isomerization and Fragmentation Reactions on the [C2SH4] Potential Energy Surface. The Metastable Thione-S-Methylide Isomer

2020 ◽  
Author(s):  
Zoi Salta ◽  
Marc E. Segovia ◽  
Aline Katz ◽  
Nicola Tasinato ◽  
Vincenzo Barone ◽  
...  
Keyword(s):  
Potential Energy ◽  
Transition State ◽  
Potential Energy Surface ◽  
Density Functional ◽  
Energy Surface ◽  
Computational Study ◽  
Experimental Information ◽  
Reaction Scheme ◽  
Ring Closure ◽  
Complete Analysis

Thione S-methylide (TSM), the parent species of the thiocarbonyl ylide family, is a 1,3-dipolar, planar species on the [C2SH4] potential energy surface (PES), which has not shared the richness of studies dedicated to its isomers, the cyclic thiirane (THI), and the keto-enol pair vinyl thiol (VTH)/thioacetaldehyde (THA). While the conrotatory ring closure reaction toward THI was studied in the ‘90s, no complete analysis of the PES is available in the literature. In the present paper, we report a computational study of the reaction scheme linking all species on that PES. We employ several levels of calculation, ranging from density functional theory (DFT), through CCSD(T) based composite schemes, to CASSCF/CASPT2 multi-reference procedures, to find the best description of TSM, its isomers, and the transition states (TSs) ruling their interconversion. Fragmentation of TSM, THA and THI were investigated and compared to the available experimental information. We found that the B2PLYP-D3 functional, contrary to M06-2XD3 or B97X-D, describes well the geometry of both TSM and the transition state connecting it to THI. The reverse barrier, from THI to TSM, amounts to 52.2 kcal mol-1 (to be compared to 17.6 kcal mol-1 for the direct one), thus explaining why, in general, thiocarbonyl ylides cannot be prepared from thiiranes. Conversion of THI to VTH implies also a large barrier, explaining why the reaction has been observed only at high temperatures. The fragmentation of THI to S(3P) or S(1D) and ethylene was also explored, together with the decomposition to H2S plus acetylene. Open species, both in triplet and singlet states, were identified as intermediates in the fragmentations, and their energies were found to be lower than the transition state for the isomerization of THI to VTH, thus explaining the preference for fragmentation over isomerization at relatively low temperatures.

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