Tschitschibabin Reaction Research Articles

Enantioselective Synthesis of 3-Allylindolizines via Sequential Rh-Catalyzed Asymmetric Allylation and Tschitschibabin Reaction.

The first highly regio- and enantioselective synthesis of 3-allylindolizines has been developed by the sequential Rh-catalyzed asymmetric allylation and Tschitschibabin reaction. Above the 20:1 branch/linear ratio, up to a 96% yield and 99% ee could be obtained with the help of tert-butyl-substituted chiral bisoxazolinephosphine ligand. In situ generated highly nucleophilic 2-alkylpyridinium ylides are utilized to undergo the asymmetric alkylation reaction before cyclization.

α-Hydroxymethylation of pyridines at a frustrated Lewis pair template.

The "η(2)-formylborane" moiety formed by CO reduction with HB(C6F5)2 at a P/B frustrated Lewis pair template undergoes a hydroxymethylation reaction at the α-position to nitrogen in pyridine or isoquinoline. The analogous reaction with pyrimidine revealed a mechanism related to the Tschitschibabin reaction.

ChemInform Abstract: Recent Progress in Synthesis and Bioactivity Studies of Indolizines

AbstractReview: 116 refs.

P‐Quinoid Compounds by Nucleophilic Aromatic Substitution with Hydride as Leaving Group

AbstractTriarylmethylium tetrafluoroborates with a sterically shielded cationic center react with selected C‐ and N‐nucleophiles under nucleophilic aromatic substitution to give dipolar p‐quinoid final products. The mechanistic rationale includes a hydride leaving group in analogy to the Tschitschibabin reaction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Aromatic azapentalenes: 1H- and (mesoionic) 2H-pyrrolotetrazoles. Part 1. Synthesis and spectral characteristics

Two separate series of the title systems have been prepared by cyclisation of tetrazolium salts having acylmethyl functions attached to both the ring carbon and the adjacent nitrogen atom (3, 4): (i) working in an acetate buffer led to 7-acyl derivatives (5, 6; Scheme 3), and (ii) treatment with anhydride–base gave 5,7-diacyl compounds by a deviating ring closure mechanism (11, 12; Scheme 4). These materials could be defunctionalised to afford pyrrolotetrazoles (7, 8) which were earlier approached in vain from the respective 5-methyltetrazolium salts (Tschitschibabin reaction). Regarding characterisation data, attention is drawn to the conspicuous spectroscopic differences between the 1H- and the 2H-system. 2H-Pyrrolotetrazoles (6, 8, 12) represent a novel class of Ramsden’s ‘type C’ heteropentalene mesoions.

The mechanism of the tschitschibabin reaction

The mechanism of the tschitschibabin reaction