An unconventional sulfur-to-selenium-to-carbon radical transfer: chemo-and regioselective cyclization of yne-ynamides
作者:Shubham Dutta、B. Prabagar、Rajeshwer Vanjari、Vincent Gandon、Akhila K. Sahoo
DOI:10.1039/c9gc03745d
日期:——
regioselective cyclization of yne-tethered-ynamides. Density functional theory studies and HRMS experiments are used to establish a reactivity scale between thiyl and selenyl radicals. The unique features of this transformation include, (1) the chemoselective reactivity of RSe˙ over RS˙, (2) regioselective RSe˙ attack on alkyne over ynamide, (3) 5-exo-dig cyclization of yne-ynamide to unusual 4-selenyl-pyrroles
Dimethyl Sulfoxide and <i>N</i>-Iodosuccinimide Promoted 5-<i>exo-dig</i> Oxidative Cyclization of Yne-Tethered Ynamide: Access to Pyrrolidones and Spiro-pyrrolidones
作者:B. Prabagar、Sanatan Nayak、Rangu Prasad、Akhila K. Sahoo
DOI:10.1021/acs.orglett.6b01149
日期:2016.7.1
5-exo-dig oxidative cyclization of an in situ generated enol equivalent of amides from ynamides bearing internal alkynes is demonstrated. The reaction allows easy access to functionalized pyrrolidone skeletons. Pyrrolidones having 3-o-biaryl motifs successfully undergo intramolecular electrophilic cyclization with the α,β-unsaturated olefin, furnishing spiro-pyrrolidone motifs. A one-pot sequential 5-exo-dig
Alkyne Versus Ynamide Reactivity: Regioselective Radical Cyclization of Yne‐Ynamides
作者:Shubham Dutta、Rajendra K. Mallick、Rangu Prasad、Vincent Gandon、Akhila K. Sahoo
DOI:10.1002/anie.201811947
日期:2019.2.18
Ynamides are typically more reactive than simple alkynes and olefins. However, a serendipitous observation revealed a rare case where the reactivity of simple alkynes exceeds that of ynamides. This led to the development of a unique sulfur‐radical‐triggered cyclization of yne‐tethered ynamides, which involves attack of the alkyne by a thiyl radical followed by cyclization with the ynamide. A wide range
Gold(I)‐Catalyzed and PTSA‐Promoted Cycloisomerization of Ynamides to Access Pyrrole Substituted α,β‐Unsaturated Ketones**
作者:Shivani Choudhary、Gayyur、Nayan Ghosh
DOI:10.1002/ejoc.202201223
日期:2023.1.24
In this work, a new ynamide scaffold has been designed, synthesized and later applied in a gold-catalyzed cycloisomerization reaction to access pyrrole containing α,β-unsaturated ketones in low-to-moderate yields. Interestingly, the trans product has been obtained as a major isomer.
Hydrative cyclization of 1,6-allenyne catalyzed by simple RhCl3 in aqueous solvent is described. This reaction proceeds in rarely reported fashion of 6-endo cyclization and provides a facile access to 5,6-dihydropyrans and 3,4-dehydropiperidines from acyclic substrates in moderate to good yields. (C) 2014 Elsevier Ltd. All rights reserved.