The Influence of Anomeric Configuration and Aglycone Structure on the Outcome of Acid‐Promoted Ring Contraction in 2,3‐Di‐ O ‐Silylated S‐Galactopyranosides

2021 ◽  
Vol 6 (24) ◽  
pp. 6223-6229
Author(s):  
Polina I. Abronina ◽  
Alexander I. Zinin ◽  
Nelly N. Malysheva ◽  
Maxim Y. Karpenko ◽  
Natalya G. Kolotyrkina ◽  
...  
Keyword(s):  
Ring Contraction ◽  
Anomeric Configuration

N-Chlorinative Ring Contraction of 1,4-Dimethoxyphthalazines via a Bicyclization/Ring-Opening Mechanism

Synthesis ◽  
2020 ◽  
Author(s):  
Jeong Kyun Im ◽  
Ilju Jeong ◽  
Jun-Ho Choi ◽  
Won-jin Chung ◽  
ByeongDo Yang ◽  
...  
Keyword(s):  
Ring Opening ◽  
Reaction Conditions ◽  
Ring Contraction ◽  
Silyl Group ◽  
Favorskii Rearrangement ◽  
Mechanistic Analysis ◽  
Group A ◽  
Overall Efficiency ◽  
Trichloroisocyanuric Acid

AbstractAn unprecedented N-chlorinative ring contraction of 1,2-diazines was discovered and investigated with an electrophilic chlorinating reagent, trichloroisocyanuric acid (TCICA). Through optimization and mechanistic analysis, the assisting role of n-Bu4NCl as an exogenous nucleophile was identified, and the optimized reaction conditions were applied to a range of 1,4-dimethoxyphthalazine derivatives. Also, an improvement of overall efficiency was demonstrated by the use of a labile O-silyl group. A bicyclization/ring-opening mechanism, inspired by the Favorskii rearrangement, was proposed and supported by the DFT calculations. Furthermore, the efforts on scope expansion as well as the evaluation of other electrophilic promoters revealed that the newly developed ring contraction reactivity is a unique characteristic of 1,4-dimethoxyphthalazine scaffold and TCICA.

scholarly journals Ring Contraction by NHC‐Induced Pnictogen Abstraction

2019 ◽  
Vol 58 (46) ◽  
pp. 16563-16568 ◽  
Author(s):  
Martin Piesch ◽  
Stephan Reichl ◽  
Michael Seidl ◽  
Gábor Balázs ◽  
Manfred Scheer
Keyword(s):  
Ring Contraction

Synthesis of the Cyclopentyl Nucleoside (−)-Neplanocin A fromD-Glucosevia Zirconocene-Mediated Ring Contraction

2005 ◽  
Vol 88 (6) ◽  
pp. 1185-1198 ◽  
Author(s):  
Leo A. Paquette ◽  
Zhenjiao Tian ◽  
Christopher K. Seekamp ◽  
Tony Wang
Keyword(s):  
Ring Contraction ◽  
Neplanocin A

ChemInform Abstract: Ring Contraction of Sulfenamides Derived from Thiochroman-4-ones.

ChemInform ◽  
2010 ◽  
Vol 25 (21) ◽  
pp. no-no
Author(s):  
C. D. GABBUTT ◽  
J. D. HEPWORTH ◽  
B. M. HERON ◽  
M. KANJIA
Keyword(s):  
Ring Contraction
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