Effect of Varying the Anionic Component of a Copper(I) Catalyst on Homologation of Arylacetylenes to Allenes by the Mannich Reaction

Abstract

The effect of varying the anionic component of a copper(I) catalyst in the homologation of terminal arylacetylenes to allenes by the Mannich reaction was investigated. Varying amounts of allenes, Mannich bases and dimers were obtained depending on the nature of the anionic component of the copper catalyst. On the other hand, Eglinton–Glaser dimerizations were achieved in high yields with 0.5 equiv. of triethylamine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Facile Synthesis of the Shape‐Persistent 4‐Hydroxybenzaldehyde Based Macrocycles and Exploration of their Key Electronic Properties: An Experimental and DFT Approach

“…[55,56] The computed CÀ H stretching vibrations were found in the range of 3018-3251 cm À 1 unscaled and 2891.73-3114.15 cm À 1 scaled. The calculated CÀ H stretching bands were scaled by a factor of 0.958 which was in good agreement with the previously reported values [45,46] as compared to the unscaled vibration bands. The PED analysis shows that CÀ H stretching mode contributes 98 % which is consistent with previous results.…”

“…However, such processes result in various problems including cost, lower yields, catalyst recovery or product extraction and purification etc. [39][40][41][42][43][44][45][46][47] After experiencing such problems, we searched for an optimized procedure and performed different experiments. Finally, we have found Cu(OAc) 2 / pyridine system as an effective mediator for alkyne homo-coupling (Table S2).…”

7‐Chloroquinoline–isatin Conjugates: Antimalarial, Antitubercular, and Cytotoxic Evaluation

“…N ‐propargylated isatin 12 was prepared by an initial treatment of isatin with sodium hydride with subsequent addition of propargyl bromide at 60 °C. The N ‐propargylated isatins 12 were then utilized in Cu( Ι )Cl catalyzed Mannich reaction with 9 in the presence of formaldehyde in dry 1,4‐dioxane (Scheme ) . Mechanistically, the reaction is thought to proceed via an initial formation of Cu‐acetylide, which undergoes a nucleophilic addition to the iminium ion formed by the condensation reaction between 9 and formaldehyde.…”

Recent advances and applications of Glaser coupling employing greener protocols

“…Chibale and co-workers observed the homocoupling of acetylenic chalcones during the synthesis of biologically active aryl acetylenic Mannich bases (Scheme 19). 41 Dimerization of acetylenic chalcones were achieved effectively in high yields with 0.5 eq. of Cu(OAc) 2 (typical Cu-mediated Glaser reactions require an excess amount (10 eq.)…”