- Synthesis of Spiro-Pyrrolidinyloxindoles by Oxidative Rearrangement of N-Acyltetrahydro-β-carbolines Using an Oxone/Aqueous Acetone Mixture
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Spiro-pyrrolidinyl-2-oxindoles were prepared by the oxidative rearrangement of Na-acetyl-1,2,3,4-tetrahydro-β-carbolines (THBC) using dimethyldioxirane generated in situ. The Na-acetyl THBC substrates were obtained by Pictet-Spengler and acyl-Pictet-Spengler reactions of L-tryptophan methyl ester, followed by Na-acetylation. The stereoselectivity of the oxidative rearrangement was evaluated and 2D nuclear magnetic resonance (NMR) was used to determine the stereochemistry of the oxindole products relative to L-tryptophan. Density functional theory calculations were consistent with a face selective, substrate controlled, epoxidation of the indolic double bond. The calculations indicated that the resulting epoxide would readily rearrange at room temperature via a concerted ring opening/ring contraction process to give the 3-substituted-2-oxindole.
- Mar?al, Luisa L.,Garden, Simon J.
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- A Direct Access to 7-Aminoindoles via Iridium-Catalyzed Mild C-H Amidation of N-Pivaloylindoles with Organic Azides
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Ir(III)-catalyzed regioselective direct C-7 amidation of indoles in reaction with organic azides has been developed. While its efficiency was varied by the choice of N-directing groups, N-pivaloylindoles were most effective in undergoing the desired amidation at room temperature over a broad range of substrates. The reaction was scalable, and deprotection of the chelation group was also facile.
- Kim, Youyoung,Park, Juhyeon,Chang, Sukbok
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supporting information
p. 1892 - 1895
(2016/05/19)
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- Direct oxidative coupling of N-acetyl indoles and phenols for the synthesis of benzofuroindolines related to phalarine
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Inspired by the biogenetic synthesis of benzofuro-indoline-containing natural products, we designed an oxidative coupling between phenol and N-acetyl indoles. This straightforward and direct radical process, mediated by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and FeCl 3 allowed the regioselective synthesis of benzofuro[3,2-b]indolines, whose structure is found in the natural product phalarine.
- Tomakinian, Terry,Guillot, Rgis,Kouklovsky, Cyrille,Vincent, Guillaume
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supporting information
p. 11881 - 11885
(2015/01/09)
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- Palladium[ii] catalysed C(sp3)-H oxidation of dimethyl carbamoyl tetrahydrocarbazoles
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Dimethyl carbamoyl tetrahydrocarbazoles undergo directed oxidation using standard conditions to exclusively provide products from C(sp3)-H oxidation. This result is in contrast to recent studies on the directed C-H olefination of hydrocarbazoles, which result in selective aromatic functionalisation.
- Nakano, Yuji,Lupton, David W.
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supporting information
p. 1757 - 1760
(2014/02/14)
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- Oxaziridine-mediated oxyamination of indoles: An approach to 3-aminoindoles and enantiomerically enriched 3-aminopyrroloindolines
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A radical solution: A highly regioselective copper(II)-catalyzed oxyamination of N-acyl indoles with oxaziridines gave aminal products that could be converted in a single step into 3-aminoindoles and 3-aminopyrroloindolines (see scheme). When a chiral N-acyl group was used, the core fragment of some architecturally fascinating pyrroloindoline alkaloids was formed with 91% ee. Bs=benzenesulfonyl, Moc=methoxycarbonyl. Copyright
- Benkovics, Tamas,Guzei, Ilia A.,Yoon, Tehshik P.
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supporting information; experimental part
p. 9153 - 9157
(2011/02/19)
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- The first method for protection-deprotection of the indole 2,3-π bond
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(Matrix presented) The scope and generality of a new reaction of indoles with MTAD is discussed. In most cases the ene-type reaction proceeds within seconds or minutes at 0°C to provide the urazole adducts in high yield. This reaction provides the first method for protecting the indole 2,3-double bond since the urazole adducts can be reconverted to the starting indole (retro-ene) simply by heating.
- Baran, Phil S.,Guerrero, Carlos A.,Corey
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p. 1999 - 2001
(2007/10/03)
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- Intermolecular Photoreactions of Phthalimide-Alkene Systems. Regio- and Stereoselective Oxetane Formation from N-Methylphthalimide and N-Acetylindole Derivatives
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Upon irradiation of N-methylphthalimide (1) in the presence of N-acylindole derivatives (2 or 11), cycloaddition occurred to give sterically hindered oxetanes (5) in moderate yields.Some reactions of these imide-oxetanes, such as formation of benzoxazepines (8 and 12) and eightmembered lactams (9 and 10), are also described.Keywords - intermolecular photoreaction; N-methylphthalimide; N-acylindole; oxetane; cycloaddition; imide-oxetane; benzoxazepine; Paterno-Buchi reaction
- Takechi, Haruko,Machida, Minoru,Kanaoka, Yuichi
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p. 3770 - 3779
(2007/10/02)
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