86864-07-5Relevant articles and documents
Visible Light-Induced, Metal-Free Denitrative [3+2] Cycloaddition for Trisubstituted Pyrrole Synthesis
Karki, Bhupal S.,Devi, Lalita,Pokhriyal, Ayushi,Kant, Ruchir,Rastogi, Namrata
supporting information, p. 4793 - 4797 (2019/11/16)
A metal-free, regioselective synthesis of trisubstituted pyrroles has been developed through a formal [3+2] cycloaddition reaction between 2H-azirines and nitroalkenes under visible light/photoredox-catalyzed conditions. The reaction proceeds through 2H-a
Synthesis of 2,2,5-Trisubstituted 2 H-Pyrroles and 2,3,5-Trisubstituted 1 H-Pyrroles by Ligand-Controlled Site-Selective Dearomative C2-Arylation and Direct C3-Arylation
Yamaguchi, Miyuki,Fujiwara, Sakiko,Manabe, Kei
supporting information, p. 6972 - 6977 (2019/09/03)
Palladium-catalyzed site-selective dearomative C2-arylation of 2,5-diaryl-1H-pyrroles with aryl chlorides was accomplished, and a series of 2,2,5-triaryl-2H-pyrroles were synthesized. In addition, the site selectivity of the reaction was switched by simply changing the ligand, and the direct C3-arylated 2,3,5-triaryl-1H-pyrroles were prepared. The obtained 2,2,5-triaryl-2H-pyrroles could be further transformed into 2,2,5,5-tetraarylpyrrolidines.
Coupling-isomerization-Stetter and coupling-isomerization-Stetter-Paal- Knorr sequences - A multicomponent approach to furans and pyrroles
Braun, Roland U.,Mueller, Thomas J. J.
, p. 2391 - 2406 (2007/10/03)
2,3,5-Trisubstituted furans 6 and 1,2,3,5-tetrasubstituted pyrroles 8 can be synthesized in good yields in a one-pot three-step three- or four-component process by a coupling-isomerization-Stetter-Paal-Knorr sequence of an electron-poor (hetero)aryl halid
A novel one-pot pyrrole synthesis via a coupling-isomerization-stetter-paal-knorr sequence
Braun, Roland U.,Zeitler, Kirsten,Mueller, Thomas J. J.
, p. 3297 - 3300 (2007/10/03)
Equation presented 1,2,3,5-Tetrasubstituted pyrroles can be synthesized in good yields in a one-pot, three-step, four-component process by a coupling-isomerization-Stetter reaction-Paal-Knorr sequence of an electron-poor (hetero)aryl halide, a terminal propargyl alcohol, an aldehyde, and a primary amine. The structures of the 1,4-diketone 4f and the pyrrole 6b were additionally supported by X-ray structure analyses.
The Diverse Carbenic and Cationic Chemistry of 3-Diazo-2,5-diphenylpyrrole
Nagarajan, M.,Shechter, H.
, p. 62 - 74 (2007/10/02)
3-Diazo-2,5-diphenylpyrrole (1) thermolyzes and photolyzes to 2,5-diphenyl-3H-pyrrolylidene (3), which inserts into methylene hydrogen of cyclohexane and methyne hydrogen of cumene.Hydrogen abstraction to give 2,5-diphenylpyrrole (7) occurs competitively in these systems.Carbene 3 reacts with cyclohexene, allylbenzene, and 2,3-dimethyl-2-butene to give 3-(allylically substituted)-2,5-diphenylpyrroles (15, 20, 21, and 29) as the only products of olefin incorporation along with 7.The initial position of the double bond in the olefin may be altered in the overall insertion process, and cyclopropanes are not isolable.The apparent behavior of 3 with saturated and olefinic hydrocarbons is as singlet 8s and triplet 9t.Reactions of 3 with anisole (31a) and with toluene (31b), benzenes substituted by electron-donor groups, result in selective ortho and/or para substitution to give 2,5-diphenyl-3-(substituted-phenyl)pyrroles (38a, 35, and 38b) and in hydrogen abstraction to 7.Insertion into the methyl groups and hydrogen abstraction also occur in reactions of 3 with 31b, yielding 3-benzyl-2,5-diphenylpyrrole (39) and 1,2-diphenylethane (40).Benzene (42a), however, reacts thermally or photolytically with 1 to form 1,3-diphenyl-2H-cyclooctapyrrole (46a), a member of a new heterocyclic system.Ring expansions to 4-, 5-, and 6-cyano-1,3-diphenyl-2H-cyclooctapyrroles (46b, 46b', and 46b'') and 4-, 5-, and 6-nitro-1,3-diphenyl-2H-cyclooctapyrroles (46c, 46c', and 46c'') are the principal reactions of 3 with benzonitrile (42b) and nitrobenzene (42c). 3-(m-Nitrophenyl)-2,5-diphenylpyrrole (47b) is also formed from 1 and 42c at 170 deg C.Thermolysis and photolysis of 1 to effect substitution and ringexpansion of benzenes may involve electrophilic attack of 8s to form spiropyrrolonorcaradienes (32).Directed heterolytic ring opening of 32 and (1,5 sigmatropic) rearrangements of hydrogen will rationalize the selective ortho and/or para substitution processes.Cyclooctapyrroles may arise from (electrocyclic) isomerization of 32 to spirocycloheptatrienes 44, (1,5 sigmatropic) rearrangement involving ring expansion to 45, and then hydrogen migration.Triplet photosensitization of 1 in 42a and 42b leads to 2,3,5-triphenylpyrrole (47a) and 3-(o-cyanophenyl)-2,5-diphenylpyrrole (47c), products of aromatic substitution rather than ring expansion.Such photolytic processes may involve generation and then addition of 9t to 42a and 42b, spin inversion of the triplet to singlet diradical intermediates, and successive hydrogen migrations.Aniline (59a), N-methylaniline (59b), and N,N-dimethylaniline are nucleophiles in that they are pyrrylated on nitrogen by 1 at 180 deg C.Primary and secondary alcohols and 1 undergo oxidation/reduction to carbonyls and 7; conversion to 3-alkoxy-2,5-diphenylpyrroles is minor except in the presence of ...
