- Assembly of 1,2,3,4-Tetrahydropyrrolo[1,2- a]pyrazines via the Domino Reaction of 2-Imidazolines and Terminal Electron-Deficient Alkynes
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The transformation of 2-imidazolines into 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazines has been realized. A pseudo-three-component reaction of 2-imidazolines with terminal electron-deficient alkynes (2 equiv) first generates imidazolidines, containing an N-vinylpropargylamine fragment. The latter can then undergo a base-catalyzed domino aza-Claisen rearrangement/cyclization reaction sequence, simultaneously constructing pyrrole and pyrazine rings. The process works in a broad substrate scope, delivering pyrrolo[1,2-a]pyrazines in good to excellent yields (45-90%). This two-step approach can be carried out in a one-pot fashion without a noticeable decrease in yield. Remarkably, a three-component protocol for the introduction of two different alkynes has been also developed.
- Festa, Alexey A.,Golantsov, Nikita E.,Golubenkova, Alexandra S.,Varlamov, Alexey V.,Voskressensky, Leonid G.
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- A Domino Route toward Polysubstituted Pyrroles from 2-Imidazolines and Electron-Deficient Alkynes
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The reaction of 1,2-disubstituted 2-imidazolines with electron-deficient alkynes proceeds as a pseudo-three-component process and forms imidazolidines with an N-vinylpropargylamine fragment. Heating the resulting imidazolidines in xylene on air leads to a
- Festa, Alexey A.,Golantsov, Nikita E.,Golubenkova, Alexandra S.,Varlamov, Alexey V.,Voskressensky, Leonid G.
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supporting information
(2020/06/29)
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- One-pot triflic anhydride-mediated synthesis of 1,2-disubstituted 2-imidazolines from N-(2-haloethyl)amides and amines
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A one-pot synthesis of 1,2-disubstituted 2-imidazolines from N-(2-haloethyl)amides has been developed. The reaction affords high yields of diverse 1,2-disubstituted 2-imidazolines from triflic anhydride-mediated dehydration of amides followed by installat
- Ellsworth, Alyssa A.,Magyar, Christina L.,Hubbell, Grace E.,Theisen, Chelsea C.,Holmes, Daniel,Mosey, R. Adam
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p. 6380 - 6389
(2016/09/23)
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- Copper-catalyzed N -arylation of 2-imidazolines with aryl iodides
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The first copper-catalyzed N-arylation of 2-imidazolines is described. The reaction affords compounds with desirable lead-like characteristics in high yield with practical simplicity under inexpensive, ligand-free conditions. The cross coupling was successful with electron-rich and electron-poor aromatic iodides. Substrates bearing halides, esters, nitriles, and free hydroxyls are well tolerated, providing reactive handles for further functionalization, as are pyridines. In addition, the regioselective N-arylation of a 4-substituted imidazoline is reported.
- Davis, Owen A.,Hughes, Matthew,Bull, James A.
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p. 3470 - 3475
(2013/06/26)
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