17017-63-9Relevant academic research and scientific papers
One-pot, three-component Fischer indolisation-N-alkylation for rapid synthesis of 1,2,3-trisubstituted indoles
Hughes-Whiffing, Christopher A.,Perry, Alexis
supporting information, p. 627 - 634 (2021/02/06)
A one-pot, three-component protocol for the synthesis of 1,2,3-trisubstituted indoles has been developed, based upon a Fischer indolisation-indoleN-alkylation sequence. This procedure is very rapid (total reaction time under 30 minutes), operationally straightforward, generally high yielding and draws upon readily available building blocks (aryl hydrazines, ketones, alkyl halides) to generate densely substituted indole products. We have demonstrated the utility of this process in the synthesis of 23 indoles, benzoindoles and tetrahydrocarbazoles bearing varied and useful functionality.
An Electrophilic Bromine Redox Catalysis for the Synthesis of Indole Alkaloid Building Blocks by Selective Aliphatic C?H Amination
Bergès, Julien,García, Belén,Mu?iz, Kilian
supporting information, p. 15891 - 15895 (2018/11/23)
A new homogeneous bromine(?I/I) redox catalysis is described, which is based on monomeric bromine(I) compounds containing transferable phthalimidato groups. These catalysts enable intermolecular C?H amination reactions at previously unaccessible aliphatic positions and thus enlarge the synthetic potential of direct C?N bond formation, including its application in the synthesis of alkaloid building blocks. This aspect is demonstrated by a new synthetic approach to aspidospermidine. In addition to the development of the catalyst system, the structures of the involved bromine(I) key catalysts were fully elucidated, including by X-ray analyses.
Iodine-catalyzed aromatization of tetrahydrocarbazoles and its utility in the synthesis of glycozoline and murrayafoline A: A combined experimental and computational investigation
Humne, Vivek,Dangat, Yuvraj,Vanka, Kumar,Lokhande, Pradeep
supporting information, p. 4832 - 4836 (2014/07/07)
A new protocol for the aromatization of tetrahydrocarbazoles has been achieved using a catalytic amount of iodine, giving high yields. The role of iodine in the aromatization has been explained by DFT, and its wide scope is extended to the total synthesis of glycozoline and murrayafoline A. This method has proven to be tolerant of a broad range of functional groups. This journal is the Partner Organisations 2014.
Indoles synthesized from amines via copper catalysis
Besandre, Ronald,Jaimes, Miguel,May, Jeremy A.
supporting information, p. 1666 - 1669 (2013/06/26)
N-Substituted indoles are synthesized from primary amines through a tandem reaction sequence. Initial condensation of the amine with an α-(o-haloaryl)ketone or aldehyde is followed by intramolecular aryl amination catalyzed by CuI. A variety of anilines and alkyl amines, including those with significant steric demands, are converted to indoles in high yields and with varying indole substitution.
Formation of enehydrazine intermediates through coupling of phenylhydrazines with vinyl halides: Entry into the Fischer indole synthesis
Zhan, Fuxu,Liang, Guangxin
, p. 1266 - 1269 (2013/03/13)
Cut to the chase: Direct formation of an enehydrazine, an intermediate in the classic Fischer indole synthesis, solves the regioselectivity problem associated with indolization. This approach not only achieves selective synthesis of indoles through proper selection of the vinyl halide, but also leads to quick construction of desoxyeseroline and esermethole, as well as the key structural motif in the Akuammiline alkaloid vincorine. Copyright
Palladium-catalyzed tandem alkenyl and aryl C-N bond formation: A cascade N-annulation route to 1-functionalized indoles
Willis, Michael C.,Brace, Gareth N.,Holmes, Ian P.
, p. 403 - 406 (2007/10/03)
(Chemical Equation Presented) A single tandem operation allows rapid access to a variety of substituted N-functionalized indoles. The nitrogen atom of the indole nucleus is incorporated through Pd-catalyzed aryl and alkenyl C-N bond-forming reactions (see scheme; dba = dibenzylideneacetone). Amine, aniline, amide, carbamate, and sulfonamide functional groups can be introduced efficiently.
Intramolecular Pd-mediated processes of amino-tethered aryl halides and ketones: Insight into the ketone α-arylation and carbonyl-addition dichotomy. A new class of four-membered azapalladacycles
Sole, Daniel,Vallverdu, Lluis,Solans, Xavier,Font-Bardia, Merce,Bonjoch, Josep
, p. 1587 - 1594 (2007/10/03)
An exploration of the scope and limitations of Pd(O)-catalyzed intramolecular coupling reactions of amino-tethered aryl halides and ketones has been conducted. Two different and competitive reaction pathways starting from ω-(2-haloanilino) alkanones, enolate arylation and addition to the carbonyl group, have been observed, while ω-(2-halobenzylamino) alkanones exclusively underwent the enolate arylation process. The dichotomy between ketone α-arylation and carbonyl-addition in the reactions of ω-(2-haloanilino) alkanones has been rationalized by the intermediacy of unprecedented four-membered azapalladacycles, from which X-ray data and chemical behavior are reported.
Synthetic Studies of Indoles and Related Compounds, Part 221. The Vilsmeier-Haack Reaction of N-Benzyl-1,2,3,4-tetrahydrocarbazoles and its Synthetic Application to Olivacine and Ellipticine2
Yokoyama, Yuusaku,Okuyama, Naomi,Iwadate, Shinji,Momoi, Tokuko,Murakami, Yasuoki
, p. 1319 - 1329 (2007/10/02)
Vilsmeier-Haack reaction of 9-benzyl-1,2,3,4-tetrahydrocarbazole (18a) at 120 deg C gave 9-benzyl-1-methylcarbazole-3-carbaldehyde (19a) and 9-benzyl-1-(N,N-(dimethylamino)methyl)carbazole-3-carbaldehyde (22a) in moderate yields, whereas, the same reaction at 0 deg C gave 9-benzyl-1,2,3,4-tetrahydrocarbazole-1-carbaldehyde (20a) in very good yield.The aldehyde (20a) was converted into 9-benzyl-1-methylcarbazole (21a) by another Vilsmeier-Haack reaction.This carbazole (21a) unexpectedly underwent non-regioselective formylation under similar reaction conditions to give a mixture of compound (19a) and 9-benzyl-8-methylcarbazole-3-carbaldehyde (23a).On the basis of the above results, a mechanism of the formation of the aromatic aldehyde (19a) was proposed, which involves 1,5-sigmatropic rearrangement of an N-methylidene dimethylammonium cation from the 4a-position to the 3-position as a key step.Vilsmeier-Haack reaction of 9-benzyl-1,2,3,4-tetrahydro-4-methylcarbazole (18b) at 100 deg C also gave 9-benzyl-1,4-dimethylcarbazole-3-carbaldehyde (19b) in moderate yield.The total syntheses of two antitumor alkaloids, olivacine (10) and ellipticine (11), were achieved by utilizing compounds (19a) and (19b) as key intermediates.
One-Pot Synthesis of Indoles from 1-Benzyl-2,3-dihydroindoles
Kiguchi, Toshiko,Kuninobu, Naoko,Takahashi, Yoshiko,Yoshida, Yukiyo,Naito, Takeaki,Ninomiya, Ichiya
, p. 778 - 781 (2007/10/02)
A facile one-pot dehydrodebenzylation of 1-benzyl-2,3-dihydroindoles to indoles uses 10percent palladium on carbon as catalyst and ammonium formate as hydrogen donor in methanol.
Carbon-Skeletal Anionic Rearrangements of Tertiary Benzylic Amines: Geometric and Electronic Requirements for Generating the Spiroazacyclopropane Intermediate
Eisch, John J.,Dua, Suresh K.,Kovacs, Csaba A.
, p. 4437 - 4444 (2007/10/02)
In order to determine the scope and mechanism for the base-promoted rearrangement of tertiary amines, a wide variety of benzylic amines were treated with n-BuLi in THF or TMEDA, n-BuLi-KO-t-Bu mixtures, or KH.The following amines were examined: benzyldimethylamine, benzylmethylphenylamine, benzyldiphenylamine, N-benzylcarbazole, N-benzyl-1,2,3,4-tetrahydrocarbazole, N-benzyl-1,1a,2,3,4,4a-cis-hexahydrocarbazole, N-(2-phenylethyl)carbazole, N-(3-phenylpropyl)carbazole, N-(2-chloroethyl)carbazole, N-benzyl-9,9-dimethyl-9,10-dihydroacridine, N-benzyl-o,o'-iminodibenzyl, 9-(diphenylamino)fluorene, 9-anilino-9-phenylfluorene, 9-(methylphenylamino)fluorene, and diphenyl(diphenylmethyl)amine.In certain cases, ethylation products were obtained from the interaction of intermediate carbanions with ethylene generated by the decomposition of THF.The results are interpreted in terms of intramolecular shifts of aryl groups from nitrogen to benzylic carbon proceeding by way of a bridging aryl transition state or intermediate.
