Cyclization reactions of 2-alkynylbenzyl alcohol and 2-alkynylbenzylamine derivatives promoted by tetrabutylammonium fluoride

An Electrochemical Alternative Approach to the Cyclization of Alkynes Bearing Proximate Malonyl Moieties

“…The beneficial effect of soft tetraalkylammoniun cations on the cyclization of alkynes bearing proximate nucleophiles has been reported in the literature. [17] We then extended the electrochemically induced cyclization reaction to the preparation of 3-pyrrolin-2-ones 5 and quinolones 6 ( Table 3). The N-propargylmalonamides 2a-b Table 2.…”

Tetra-n-butylammonium fluoride-mediated dimerization of (α-methylbenzylidene)malononitriles to form polyfunctional 5,6-dihydropyridines derivatives under solvent-free conditions

“…The resulting mixture was stirred for additional 5 min and then formed precipitate was filtered and washed with more 1.0 M HCl to give the pure compounds 28-46 in good to excellent yield (52 to 95%). The structure of these compounds 28-46 was confirmed by using different spectroscopic techniques including 1 H NMR, 13 C NMR, EI-HRMS and IR spectroscopy. 13 13 …”

“…The structure of these compounds 28-46 was confirmed by using different spectroscopic techniques including 1 H NMR, 13 C NMR, EI-HRMS and IR spectroscopy. 13 13 …”

“…TBAF (Tetrabutylammonium fluoride) is commonly used as desylating agent in organic reactions [9]. However, in last few years chemists have explored many utilities of this reagent which involves nucleophilic substitution to synthesize organofluoro compounds [10], cyclization reactions to produce different heterocyclic rings systems via 5-exo-dig cyclization or 6-endo-dig cyclization [11][12][13], oxidation of aromatic aldehydes to benzoic acid [14] [3+2]-cycloaddition (click chemistry) [15] and [4+2]-cycloaddition [16].…”

Facile access to cyclooctanoid ring systems via microwave-assisted tandem 6-exo dig cyclization–rearrangement sequence

“…Although anionic 5-exo dig cyclizations involving oxygen nucleophiles have been known since the early 1950’s, 7 these transformations are generally difficult to achieve due to the reversibility and unfavorable equilibria associated with such isomerizations, particularly with unactivated alkynes. In addition, the initially formed exocyclic vinyl ethers are often unstable 8 and isomerize easily to form the corresponding endocyclic derivatives. 9 …”