On the Role of Neighboring Group Participation and Ortho Esters in β-Xylosylation: 13C NMR Observation of a Bridging 2-Phenyl-1,3-dioxalenium Ion

1999 ◽  
Vol 64 (14) ◽  
pp. 5224-5229 ◽  
Author(s):  
David Crich ◽  
Zongmin Dai ◽  
Stéphane Gastaldi
Keyword(s):  
13C Nmr ◽  
Neighboring Group ◽  
Group Participation ◽  
Ortho Esters ◽  
Neighboring Group Participation

Role of neighboring group participation in the acetolysis of .alpha.-(phenylthio)-.omega.-[(p-tolylsulfonyl)oxy]alkanes

1987 ◽  
Vol 52 (18) ◽  
pp. 4094-4098 ◽  
Author(s):  
Vittorio Rosnati ◽  
Antonio Saba ◽  
Antonella Angius ◽  
Daniele Casarini
Keyword(s):  
Neighboring Group ◽  
Group Participation ◽  
Neighboring Group Participation

Further studies on the role of neighboring group participation in carbonyl substitution reactions of group 6 metal carboxylates

1991 ◽  
Vol 30 (5) ◽  
pp. 1137-1142 ◽  
Author(s):  
Donald J. Darensbourg ◽  
Jennifer A. Joyce ◽  
Christopher J. Bischoff ◽  
Joseph H. Reibenspies
Keyword(s):  
Substitution Reactions ◽  
Metal Carboxylates ◽  
Neighboring Group ◽  
Group Participation ◽  
Group 6 ◽  
Carbonyl Substitution ◽  
Neighboring Group Participation

Neighboring group participation in electrophilic additions: The role of Markovnikov and Fürst-Plattner rule in hypobromous acid addition to 5,6-unsaturated cholestane derivatives

1983 ◽  
Vol 48 (12) ◽  
pp. 3618-3628 ◽  
Author(s):  
Pavel Kočovský
Keyword(s):  
Methyl Ether ◽  
Hydroxyl Group ◽  
Unsaturated Alcohol ◽  
Neighboring Group ◽  
Group Participation ◽  
Acid Addition ◽  
Hypobromous Acid ◽  
Neighboring Group Participation ◽  
Electrophilic Additions

On reaction with hypobromous acid, the unsaturated alcohol IIIa yields the diequatorial bromo epoxide XIX arising from the 5α,6α-bromonium ion XVIIIa on cleavage at C(5) by 19b-hydroxyl group with 6(O)n participation. By contrast, the bromonium ion XVIIIb generated from the unsaturated methyl ether IIIb is cleaved by water as external nucleophile to yield the unstable diaxial bromohydrin XX which undergoes cyclization to the oxirane derivative XXI. A comparison with the reaction course in homologs of the type I and II permits the conclusion that the change in regioselectivity, generally possible outcome of the 5(O)n participation, is only possible for the 6(O)n process if the participating group is a hydroxyl.

scholarly journals Water-promoted Synthesis of Stereoselective Oxazoline-fused Saccharides and Construction for 1, 2-cis Glycosylamines of Multi-modifications of Polyhydroxyl groups

2020 ◽  
Author(s):  
Sanfeng Dong ◽  
Yitian Zhao ◽  
Yulong Shi ◽  
Zhijian Xu ◽  
Jingshan Shen ◽  
...  
Keyword(s):  
Density Functional ◽  
Chiral Molecules ◽  
Functional Theory ◽  
Neighboring Group ◽  
Group Participation ◽  
Glycosidic Bonds ◽  
The Density Functional Theory ◽  
Acidic Conditions ◽  
Neighboring Group Participation

Abstract The multi-modifications of polyhydroxyl groups and the stereoselective formation of 1,2-cis glycosidic bonds are difficult in glycochemistry. Herein we disclosed a concise synthesis of the oxazoline-fused saccharides (oxazolinoses) from acetyl saccharides and benzonitriles under acidic conditions promoted by the stoichiometric water. The oxazolinoses can be easily converted into 1,2-cis glycosylamines with differentiated modifications at 2,3-positions on the saccharide ring in few steps and the 1-NH2 can further be simply transformed to the 1-OH. Oxazolinoses can also be directly used to synthesize complex chiral molecules such as schisandrins. Saccharides screening have shown that the oxazolinoses could be synthesized from various monosaccharides and oligosaccharides. Accordingly, 1-α- or 1-β-1,2-cis glycosylamines can be obtained from different oxazolinoses which are 1,2-cis stereoselectivity controlled by neighboring group participation. The density functional theory (DFT) calculations have revealed the origin of the stereoselectivity and the key role of water.

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