- Rh(III) and Ir(III)Cp? Complexes Provide Complementary Regioselectivity Profiles in Intermolecular Allylic C-H Amidation Reactions
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An efficient regioselective allylic C-H amidation of mono-, di-, and trisubstituted olefins has been developed. Specifically, the combination of dioxazolone reagents with RhCp? and IrCp? catalysts is reported to promote reactions with complementary regios
- Burman, Jacob S.,Harris, Robert J.,Farr, Caitlin M. B.,Bacsa, John,Blakey, Simon B.
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- Ir-Catalyzed Intermolecular Branch-Selective Allylic C-H Amidation of Unactivated Terminal Olefins
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An efficient method for intermolecular branch-selective allylic C-H amidation has been accomplished via Ir(III) catalysis. The reaction proceeds through initial allylic C-H activation, supported by the isolation and crystallographic characterization of an allyl-Ir(III) intermediate, followed by a subsequent oxidative amidation with readily available dioxazolones as nitrenoid precursors. A diverse range of amides are successfully installed at the branched position of terminal alkenes in good yields and regioselectivities. Importantly, the reaction allows the use of amide-derived nitrenoid precursors avoiding problematic Curtius-type rearrangements.
- Lei, Honghui,Rovis, Tomislav
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- Intermolecular, Branch-Selective, and Redox-Neutral Cp*IrIII-Catalyzed Allylic C?H Amidation
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Herein, we report the redox-neutral, intermolecular, and highly branch-selective amidation of allylic C?H bonds enabled by Cp*IrIII catalysis. A variety of readily available carboxylic acids were converted into the corresponding dioxazolones and efficiently coupled with terminal and internal olefins in high yields and selectivities. Mechanistic investigations support the formation of a nucleophilic IrIII–allyl intermediate rather than the direct insertion of an Ir–nitrenoid species into the allylic C?H bond.
- Knecht, Tobias,Mondal, Shobhan,Ye, Jian-Heng,Das, Mowpriya,Glorius, Frank
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supporting information
p. 7117 - 7121
(2019/04/30)
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- Determination of the Absolute Configuration of (S)-N-(1-Aryl-allyl)-3,5-dinitrobenzamides and Their Elution Order on Brush-Type Chiral Stationary Phases
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A series of ten enantiomerically pure (S)-N-(1-aryl-allyl)-3,5-dinitrobenzamides (S-DNBs) was prepared using enzymatic resolution and chiral chromatography. Enzymatic resolution of corresponding 1-aryl-allylamines using Candida antarctica lipase B (CaLB) was efficient for amines with no steric hindrance near the stereogenic center and S-DNB amides were prepared by acylation of the obtained S-amine. When steric effects interrupted enzymatic resolution, racemic DNB amides were resolved using a brush-type chiral column (CSP-A) developed in our laboratory. Previously reported behavior of CaLB in kinetic resolution of amines was considered a starting point for the determination of absolute configuration (AC). The AC of prepared S-DNB amides was anticipated using the elution order of prepared DNB amides on CSP-A and commercial Whelk-O1 columns and comparison with DNB amides obtained after acylation of (S)-amines. The comparison between experimental electronic circular dichroism (ECD) spectra with those obtained by conformational analysis and ECD calculations of representative compounds allowed us to verify the AC of prepared DNB amides.
- Kne?evi?, Anamarija,Novak, Jurica,Pescitelli, Gennaro,Vinkovi?, Vladimir
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p. 3982 - 3991
(2018/08/07)
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- Enantioselective synthesis of 1-aryl-2-propenylamines: A new approach to a stereoselective synthesis of the Taxol side chain
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A variety of substituted 1-aryl-2-propenylamines of high enantiomeric purity were prepared via lipase-catalysed resolution of the corresponding racemates. (R)-1-Phenyl-2-propenylamine was further synthesised into (2R,3S)-3-benzoylamino-2-hydroxy-3-phenylpropanoic acid methyl ester, the side chain of Taxol.
- Castagnolo, Daniele,Armaroli, Silvia,Corelli, Federico,Botta, Maurizio
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p. 941 - 949
(2007/10/03)
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- Novel, Regioselective Allylamine Construction; First Synthesis of Geranyllinaloisocyanide, a Diterpene from the Marine Sponge, Halichondria Sp.
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The first synthesis of the diterpene, 3-isocyano-3,7,11,15-tetramethylhexadeca-1,6,10,14-tetraene (geranyllinaloisocyanide, 1), has been achieved through an allyl cyanate-to-isocyanate rearrangement.The crucial step in this synthesis is in situ transformation of allyl isocyanates into stable allyl acetamides with trimethylaluminium.
- Ichikawa, Yoshiyasu,Yamazaki, Masatugu,Isobe, Minoru
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p. 2429 - 2432
(2007/10/02)
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