LEWIS ACID
‘Frustrated’ Lewis pairs: From Lewis acid -base adducts to the reversible, metal-free activation of hydrogen
... ‘Frustrated’ Lewis pairs: From Lewis acid -base adducts to the ‘Frustrated’ Lewis pairs: From Lewis acid -base adducts to the reversible, metal-free activation of hydrogen.. reversible[r] ...
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PART I: SYNTHESIS OF A-RING MODIFIED ALLOCOLCHICINOIDS VIA LEWIS ACID CATALYZED CONJUGATE ADDITION REACTIONS; PART II: PREPARATION OF BENZOCYCLOHEPTADIENYNOL-Co2(CO)6 COMPLEXES
... Lewis acid to be selected as a suitable mediator for the 7-exo-trig process. The success of the cyclization process was variable from one substrate to another. Substrate (80a), bearing an electron-donating ...
206
Lewis acid-catalyzed cycloaddition reactions of donor-acceptor cyclopropanes
... In summary, a Lewis acid-catalyzed [3 + 2] cycloaddition reaction of carbon- based D-A cyclopropanes and aldehydes has been developed. This methodology achieves the facile synthesis of cis-2,5-disubstituted ...
146
Synthesis of Polysilanes Using Mg and Lewis Acid and the Consideration of This Reaction Mechanism
... (m, Me), and 6.30 - 7.70 (m, Ph), however, exact proportion between methyl protons and ring proton of 2a was 3.3:5.0 and that of 2b was 3.1:5.0 (theoretical value is 3.0:5.0). This means that 2a has more branched Si ...
15
A New Facile Route to Chlorination of Alcohols via Lewis Acid AlCl3
... ingly, different transformation was occurred, chlorinated product was obtained with excellent yields (Scheme 1). In this communication, we wish to report our preliminary investigation on the solvent modulated ...
5
Lewis acid-promoted Friedel-Crafts alkylation of alpha-ketophosphate electrophiles
... Using ortho-methoxy substituted ketone 15a as the standard electrophile, we investigated the limits of nucleophilic incorporation. The results are summarized in Table 1- 6. Both aromatic and heteroaromatic nucleophiles ...
189
Lewis acid-promoted cycloaddition reactions of aziridines and cyclopropanes
... The chemistry of aziridines is dominated by the reactivity of the carbon-nitrogen bonds. 26 The most notable exception to this reactivity pattern is the thermal or photochemical electrocyclic ring opening of aziridines ...
190
Structure activity correlations for Brønsted acid, Lewis Acid, and photocatalyzed reactions of exfoliated crystalline niobium oxides
... is acid site in a photocatalyst. 12 However, Lewis acid catalysed reactions can be fundamentally different from ...the Lewis acid site-substrate transition state at excited state does ...
11
Enantioselective Diels-Alder reactions of carboxylic ester dienophiles catalysed by titanium-based chiral Lewis acid
... In this work, it was found that high enantioselectivities are possible for Diels-Alder reaction of carboxylic esters catalysed by titanium- based chiral Lewis acid. It may be happening because of ...
6
Lewis acid promoted hydrofluorination of alkynyl sulfides to generate α fluorovinyl thioethers
... the Lewis acid acts to increase the acidity of the 3HF·Et 3 N by sequestering fluoride ions as relatively unreactive metal fluo- rides; thus, the alkynyl sulfides are activated by protonation possibly ...
8
Functionalization of ε-Carbonyl Cation Equivalents Facilitated by Lewis Acid Catalysts
... containing Lewis basic components tended to not work very well (Figure ...an acid-base reaction occurring between the nucleophile and Lewis acid, instead of the desired ...of Lewis ...
116
Synthesis of mesoporous alumina nanoparticle using agarose template for lewis acid catalyst
... In this study, attempt to prepare porous alumina by sol gel synthesis by using biomaterial agarose gel template is being carried out. Agarose gel is chosen over other biomaterials due to its availability and lowest. ...
29
Lewis acid promoted (3+2) cycloadditions and multi component reactions of methyleneaziridines
... Chapter two describes the discovery and development of a novel Lewis acid- promoted (3+2) cycloaddition reaction of methyleneaziridines onto alkyne and alkene acceptors. Both inter- and intramolecular ...
242
C5–C7 linear alkane hydroisomerization over MoO3–ZrO2 and Pt/MoO3–ZrO2 catalysts
... then was observed by IR and ESR spectroscopy (Figs. 5–7). We have previously reported the hydrogen spillover phenomenon over zirco- nia- and zeolite-based catalysts in which the molecular hydrogen dissociatively adsorbed ...
10
Catalytic Esterification of Medium Chain Fatty Acids: Kinetic Investigations
... C10:0) acid is a solid; with boiling temperature increasing from 478 K, 510 K to 543 K, ...caprylic acid and mono- and dicaprylates, often they are a mixture of caproic, caprylic and capric acids [1] ...
10
Spectrophotometric Method for the Determination of Sulfa Drug in Pharmaceuticals Based on Charge Transfer Reaction
... (picric acid) as Lewis acid to the secondary amino group of sulfamethoxazole and sulfamerazine as Lewis base in methanol to form a yellow charge transfer complex exhibiting maximum absorption ...
8
SYNTHETIC STUDIES TOWARDS SYNTHESIS OF C27-C40 FRAGMENT OF AZASPIRACID
... during acid and Lewis acid catalyzed acetonide deprotection of compound 48 of section B, it was decided to change all the protecting groups and acetonide group was removed in early stage and ...
22
Efficient Conversion of Glucose into
... Lewis acid sites catalyst [34-38] and Lewis acid sites own high isomerization of glucose into fructose. 204[r] ...
15
Determination of Lewis and Brönsted acid sites by gas flow-injection technique
... Since the large application and the experimental reasons, in situ apparatus of IR spectroscopy of pyridine adsorption was successfully extensively developed. However, this technique apparatus is commonly designed for ...
5
Microwave assisted synthesis of Isoflavones
... arylboronic acid with aryl chromanones using tetrakis(triphenylphosphine) palladium catalyst called coupling ...acetic acid in presence of BF 3 etherate as a Lewis ...
6