Ring Opening and Rearrangement of a Nitro-Capped Cobalt(III) Cage Complex With an N3S3 Donor Set

1994 ◽  
Vol 47 (5) ◽  
pp. 807 ◽  
Author(s):  
P Osvath ◽  
AM Sargeson
Keyword(s):  
Ring Opening ◽  
Hydride Transfer ◽  
Strong Acid ◽  
Amine Group ◽  
Type Reaction ◽  
Cage Complex ◽  
Methylene Unit ◽  
Excess Base

Treatment of the N3S3 donor cage complex [Co(NO2-capten)]3+ (1-methyl-8-nitro-3,13,16-trithia-6,10,19-triazabicyclo[6.6.6]icosanecobalt(III)) with excess base leads to deprotonation of a secondary coordinated amine group, followed by loss of a methylene unit from the cap by a retro-Mannich type reaction. Subsequent intermolecular hydride transfer gives a novel oxidized and partly delocalized macrocyclic complexed carbanion (13-(4-amino-2-thiabutyl)-13-methyl-6-nitro-1,11-dithia-4,8-diazacyclotetradec-4-enato(6)cobalt(III)) that is stabilized by deprotonation, and which remains deprotonated even in strong acid.

Hydride Transfer Ring-Opening Polymerization of a Cyclic Oligomethylhydrosiloxane. Route to a Polymer of Closed Multicyclic Structure

2012 ◽  
Vol 45 (6) ◽  
pp. 2654-2661 ◽  
Author(s):  
Julian Chojnowski ◽  
Jan Kurjata ◽  
Witold Fortuniak ◽  
Slawomir Rubinsztajn ◽  
Barbara Trzebicka
Keyword(s):  
Ring Opening ◽  
Hydride Transfer ◽  
Ring Opening Polymerization

scholarly journals Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides

2015 ◽  
Vol 11 ◽  
pp. 1649-1655 ◽  
Author(s):  
Hanmo Zhang ◽  
E Ben Hay ◽  
Stephen J Geib ◽  
Dennis P Curran
Keyword(s):  
Carbonyl Group ◽  
Ring Opening ◽  
Radical Cyclizations ◽  
Type Reaction ◽  
Primary Products ◽  
Lactam Carbonyl Group ◽  
Lactam Carbonyl ◽  
Imine Reduction ◽  
Derivatives Of

Two new fates of imine intermediates formed on radical cyclizations of ene-sulfonamides have been identified, reduction and hydration/fragmentation. Tin hydride-mediated cyclizations of 2-halo-N-(3-methyl-N-sulfonylindole)anilines provide spiro[indoline-3,3'-indolones] or spiro-3,3'-biindolines (derived from imine reduction), depending on the indole C2 substituent. Cyclizations of 2-haloanilide derivatives of 3-carboxy-N-sulfonyl-2,3-dihydropyrroles also presumably form spiro-imines as primary products. However, the lactam carbonyl group facilitates the ring-opening of these cyclic imines by a new pathway of hydration and retro-Claisen-type reaction, providing rearranged 2-(2'-formamidoethyl)oxindoles.

scholarly journals Gold-Catalyzed Rearrangement of (Silylcyclopropenyl)methyl Ethers into (Silylmethylene)cyclopropanes

Synthesis ◽  
2016 ◽  
Vol 48 (19) ◽  
pp. 3165-3174 ◽  
Author(s):  
Florence Hiault ◽  
Alexis Archambeau ◽  
Frédéric Miege ◽  
Christophe Meyer ◽  
Janine Cossy
Keyword(s):  
Ring Opening ◽  
Methyl Formate ◽  
Hydride Transfer ◽  
Membered Ring ◽  
Allylic Cation ◽  
High Yields

Methoxymethyl ethers derived from 2-(dimethylphenylsilyl)cycloprop-1-enyl carbinols undergo gold-catalyzed rearrangement leading to [(Z)-(dimethylphenylsilyl)methylene]cyclopropanes in moderate to high yields with methyl formate as a byproduct. This transformation proceeds by initial regioselective ring opening of the three-membered ring leading to an α-silyl vinyl gold carbenoid. This latter organogold species evolves by 1,5-hydride transfer, which triggers subsequent rearrangement involving loss of methyl formate, 2π-electrocyclization of the resulting allylic cation, and elimination of the metal to regenerate the catalyst.

scholarly journals An Efficient and Mild Method for the Synthesis and Hydrazinolysis ofN-Glyoxylamino Acid Esters

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Ayman El-Faham ◽  
Zainab Al Marhoon ◽  
Ahmed Abdel-Megeed ◽  
Mohamed Siddiqui
Keyword(s):  
Hydrazine Hydrate ◽  
Good Yield ◽  
Acid Ester ◽  
Ring Opening ◽  
Acid Hydrazide ◽  
Type Reaction ◽  
H Nmr ◽  
Elemental Microanalysis ◽  
Acid Esters ◽  
C Nmr

N-Glyoxylamino acid ester derivatives were synthesized via the ring opening ofN-acetylisatin using moderate conditions. During the hydrazinolysis ofN-glyoxylamino acid ester derivatives with hydrazine hydrate (80%) in methanol, unexpected reduction of theα-keto group occurred to affordN-acylamino acid hydrazide derivatives in good yield (80–90%) (Wolff-Kishner type reaction). All the synthesized compounds were characterized by1H NMR,13C NMR, and elemental microanalysis.

Diastereoselective ring-opening aldol-type reaction of 2,2-dialkoxycyclopropanecarboxylic esters with carbonyl compounds. 2. Synthesis of cis-2,3-substituted-γ-lactones

Tetrahedron ◽  
1993 ◽  
Vol 49 (8) ◽  
pp. 1589-1604 ◽  
Author(s):  
Shigeru Shimada ◽  
Yukihiko Hashimoto ◽  
Tadamichi Nagashima ◽  
Masaki Hasegawa ◽  
Kazuhiko Saigo
Keyword(s):  
Carbonyl Compounds ◽  
Ring Opening ◽  
Type Reaction
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