Catalysis of chlorosilane on the ring-expansion of cyclic acetals bearing a carbene precursor. Lewis acid–base effect on the oxonium ylide intermediate

1999 ◽  
pp. 1339-1340 ◽  
Author(s):  
Takashi Mori ◽  
Akira Oku
Keyword(s):  
Lewis Acid ◽  
Ring Expansion ◽  
Acid Base ◽  
Cyclic Acetals ◽  
Oxonium Ylide

Polycyclic oxonium ylides — Use of cyclic acetals as convenient scaffolds in the construction of fused bicyclic compounds containing a medium ring

2006 ◽  
Vol 84 (10) ◽  
pp. 1470-1486 ◽  
Author(s):  
Graham K Murphy ◽  
Fredrik P Marmsäter ◽  
F G West
Keyword(s):  
Ring Expansion ◽  
Major Product ◽  
Side Chains ◽  
Cyclic Acetals ◽  
Bicyclic Compounds ◽  
Oxonium Ylides ◽  
Sulfonium Ylide ◽  
Oxonium Ylide ◽  
Medium Ring

Cyclic mixed acetals with pendant diazoketone side chains undergo efficient rearrangement to ether-bridged cyclooctanoid and cycloheptanoid systems upon treatment with Cu(hfacac)2. Stevens [1,2]-shift of an oxonium ylide furnishes the major product, in some cases accompanied by minor amounts of a product resulting from [1,2]-shift of a sulfonium ylide. These results demonstrate that hetero-substituted carbons are suitable migrating groups for the Stevens [1,2]-shift of oxonium ylides. In cases employing a mixed thioacetal, the resulting sulfide served as a trigger for cleavage of the bridging ether through one of two complementary strategies. In the hydrazulene series, the desired bicyclo[5.3.0]heptene was accompanied by the product of novel transannular SN2′ attack on the resulting allylic ketal.Key words: [1,2]-shift, diazo, medium-sized ring, oxonium ylide, ring expansion.

Solvation and redox properties of [Co(en)3]3+-[Co(en)3]2+ system

1980 ◽  
Vol 45 (2) ◽  
pp. 335-338 ◽  
Author(s):  
Adéla Kotočová ◽  
Ulrich Mayer
Keyword(s):  
Hydrogen Bond ◽  
Lewis Acid ◽  
Specific Interaction ◽  
Redox Properties ◽  
Solvation Effect ◽  
Interacting Particles ◽  
Acid Base ◽  
Polar Solvents ◽  
Oxidation Reduction ◽  
Solvent Molecules

The solvation effect of a number of nonaqueous polar solvents was studied on the oxidation-reduction properties of the [Co(en)3]3+-[Co(en)3]2+ system. Interactions of these ions with the solvent molecules are discussed in terms of their coordination, which is accompanied by a specific interaction of the Lewis acid-base type, namely formation of a hydrogen bond between the interacting particles. This is the main controlling factor of the redox properties of the studied system.

Chalcogen versus Dative Bonding in [SF3]+ Lewis Acid–Base Adducts: [SF3(NCCH3)2]+, [SF3(NC5H5)2]+, and [SF3(phen)]+ (phen = 1,10-phenanthroline)

2021 ◽  
Vol 60 (6) ◽  
pp. 3893-3901
Author(s):  
Douglas Turnbull ◽  
Praveen Chaudhary ◽  
Paul Hazendonk ◽  
Stacey D. Wetmore ◽  
Michael Gerken
Keyword(s):  
Lewis Acid ◽  
Acid Base

scholarly journals Lewis acid / Base-free Strategy for the Synthesis of 2-Arylthio and Selenyl Benzothiazole / Thiazole and Imidazole

2021 ◽  
Vol 27 (1) ◽  
pp. 17-23
Author(s):  
Guniganti Balakishan ◽  
Gullapalli Kumaraswamy ◽  
Vykunthapu Narayanarao ◽  
Pagilla Shankaraiah
Keyword(s):  
Lewis Acid ◽  
Bond Formation ◽  
Acid Base ◽  
Mechanistic Pathway ◽  
Wide Range ◽  
Acid And Base ◽  
Lewis Acid And Base ◽  
Sulfur Bond

Abstract A Cu(II)-catalyzed Csp2-Se and Csp2-Sulfur bond formation was achieved with moderate to good yields without the aid of Lewis acid and base. The reaction is compatible with a wide range of heterocycles such as benzothiazole, thiazole, and imidazole. Also, this typical protocol is found to be active in thio-selenation via S-H activation. Additionally, we proposed a plausible mechanistic pathway involving Cu(III) putative intermediate.

scholarly journals Novel hydrogen chemisorption properties of amorphous ceramic compounds consisting of p-block elements: exploring Lewis acid-base Al–N pair site formed in-situ within polymer-derived silicon-aluminum-nitrogen-based system

2021 ◽  
Author(s):  
Shotaro Tada ◽  
Norifumi Asakuma ◽  
Shiori Ando ◽  
Toru Asaka ◽  
Yusuke Daiko ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Active Site ◽  
Hydrogen Chemisorption ◽  
Acid Base ◽  
Polymer Derived Ceramics ◽  
System P ◽  
Ceramic Compounds ◽  
The Relationship

This paper reports on the relationship between the H2 chemisorption properties and reversible structural reorientation of the possible active site around Al formed in-situ within polymer-derived ceramics (PDCs) based on...

Manipulation of Lewis acid–base complexation in the Zr-centered quaternary system for monodisperse spherical zircons

2020 ◽  
Author(s):  
Shan Peng ◽  
Zhongqiu Chen ◽  
Qing Huang ◽  
Xiaohong Xia ◽  
Zhuo Wang ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Quaternary System ◽  
Acid Base
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