Radical Enamination of Vinyl Azides: Direct Synthesis of N-Unprotected Enamines
摘要:
An electron-withdrawing-group-generable radical-induced enamination of vinyl azides is reported, which results in a variety of beta-functionalized N-unprotected enamines in a stereoselective manner. A plausible mechanism involving an unusual 1,3-H transfer of in situ generated iminyl radical intermediate was proposed on the basis of experimental results and DFT calculations.
A novel and versatile method for the synthesis of 2H-imidazoles via iron-catalyzed [3 + 2] annulation from readily available oxime acetates with vinyl azides has been developed. This denitrogenative process involved N–O/N–N bond cleavages and two C–N bond formations to furnish 2,4-substituted 2H-imidazoles. This protocol was performed under mild reaction conditions and needed no additives or ligands
Synthesis of Isoquinoline Derivatives via Palladium‐Catalyzed C−H/C−N Bond Activation of
<i>N</i>
‐Acyl Hydrazones with
<i>α</i>
‐Substituted Vinyl Azides
A palladium‐catalyzed cyclization of N‐acetyl hydrazones with vinyl azides has been developed. Various substituted isoquinolines, including diverse fused isoquinolines can be prepared via this protocol in moderate to good yields. Mechanistic studies suggest that α‐substituted vinyl azide serves as an internal nitrogen source. Also, C−H bond activation and C−N bond cleavage have been realized using
Electrochemical Synthesis of
<i>O</i>
‐Phthalimide Oximes from
<i>α</i>
‐Azido Styrenes
<i>via</i>
Radical Sequence: Generation, Addition and Recombination of Imide‐
<i>N</i>
‐Oxyl and Iminyl Radicals with C−O/N−O Bonds Formation
作者:Stanislav A. Paveliev、Artem I. Churakov、Liliya S. Alimkhanova、Oleg O. Segida、Gennady I. Nikishin、Alexander O. Terent'ev
DOI:10.1002/adsc.202000618
日期:2020.9.21
Electrochemically induced radical‐initiated reaction of vinyl azides with N‐hydroxyphthalimide resulting O‐phthalimide oximes with challenging for organic chemistry N−O‐N fragment has been discovered. The developed approach introduces in synthesis electrochemically generated O‐centered imide‐N‐oxyl radicals as the coupling components. Sequential formation of C−O and N−O bonds was achieved via generation
Cerium(IV) ammonium nitrate promoted synthesis of O-phthalimide oximes from vinyl azides and N-hydroxyphthalimide
作者:Stanislav A. Paveliev、Liliya S. Alimkhanova、Anna V. Sergeeva、Alexander O. Terent'ev
DOI:10.1016/j.tetlet.2020.152533
日期:2020.11
O-Phthalimide oximes with an NON fragment were synthesized in high yields via the reaction of vinyl azides with phthalimide-N-oxyl radicals derived from N-hydroxyphthalimide under the action of cerium(IV) ammonium nitrate. The disclosed process is based on the radical transformation of vinyl azides with the elimination of nitrogen and the formation of iminyl N-radicals. The developed approach exploited
Indium(III) Catalyzed Reactions of Vinyl Azides and Indoles
作者:Atul A. More、Alex M. Szpilman
DOI:10.1021/acs.orglett.0c00919
日期:2020.5.15
Indium trichloride catalyzes the reaction of vinyl azides with unfunctionalized indoles to give vinyl indoles. This is the first example of displacement of the azide group by a carbon nucleophile while preserving the vinyl function. The protocol employs very mild reaction conditions and offers excellent yields of diverse 3-vinyl indoles. It is amenable to gram scale. Access to a library of 3,3'-bis(indolyl)methanes