Sequential <i>N</i>-Acylamide Methylenation−Enamide Ring-Closing Metathesis:  Construction of Benzo-Fused Nitrogen Heterocycles

Bennasar, M.‐Lluïsa; Roca, Tomas; Monerris, Manuel; García-Díaz, Davinia

doi:10.1021/jo061180j

Cited by 67 publications

(26 citation statements)

References 41 publications

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“…o -Allylaniline 37 (120 mg, 0.90 mmol, 1 equiv) was dissolved in dry CH 2 Cl 2 (4.5 mL) and the solution was treated with 3,5-di- tert -butylbenzene sulfonyl chloride 38,39 (286 mg, 0.99 mmol, 1.1 equiv) and Et 3 N (0.38 mL, 2.7 mmol, 3 equiv). The mixture was stirred at room temperature overnight, washed with 1 N HCl (5.0 mL) and extracted with CH 2 Cl 2 (3 × 8 mL).…”

Section: Methodsmentioning

confidence: 99%

Mechanistic Analysis and Optimization of the Copper-Catalyzed Enantioselective Intramolecular Alkene Aminooxygenation

2012

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The catalytic asymmetric aminooxygenation of alkenes provides an efficient and straightforward approach to prepare chiral vicinal amino alcohols. We have reported a copper(II)-catalyzed enantioselective intramolecular alkene aminooxygenation, using (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) as the oxygen source, which results in the synthesis of chiral indolines and pyrrolidines. Herein we disclose that kinetics studies indicate the reaction is first order both in substrate and the [Cu(R,R)-Ph-bis(oxazoline)]OTf2 catalyst, and zero order in TEMPO. Furthermore, kinetic isotope effect studies support that the cis aminocupration step, the addition of N-Cu across the alkene, is the rate-limiting step. Subsequent formation of a carbon radical intermediate, and direct carbon radical trapping with TEMPO is the indicated mechanism for the C-O bond formation as suggested by a deuterium labeling experiment. A ligand screen revealed that C(4)-phenyl substitution on the bis(oxazoline) is optimal for high asymmetric induction. The size of the substrate’s N-sulfonyl group also influences the enantioselectivity of the reaction. The preparative scale catalytic aminooxygenation reaction (gram scale) was demonstrated and an unexpected dependence on reaction temperature was uncovered on the larger scale reaction.

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Section: Methodsmentioning

confidence: 99%

Mechanistic Analysis and Optimization of the Copper-Catalyzed Enantioselective Intramolecular Alkene Aminooxygenation

2012

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“…[1a,5e, 6] Tw om ethods have been reported for the synthesis of carbazole derivatives from 3-formyl-substituted indoles through RCM-aromatization sequences. [3] Herein, we disclose af acile synthetic approach to naturally occurring carbazole alkaloids from isatin derivatives by the use of RCM [7] and an ovel rearrangement as the key steps.W ea nticipated that carbazole derivatives 1 could be constructed by the ring rearrangement-aromatization of spirocyclic isatin derivatives 2,w hich could be derived from 2,2-diallyl 3-oxindoles 3 by RCM (Scheme 1). The2 ,2-diallyl 3-oxindoles 3 could be readily prepared by the addition of allyl metal reagents to the readily available isatin derivatives.…”

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confidence: 99%

Synthesis of Carbazole Alkaloids by Ring‐Closing Metathesis and Ring Rearrangement–Aromatization

et al. 2015

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Aprocess for the assembly of carbazole alkaloids has been developed on the basis of ring-closing metathesis (RCM) and ringrearrangement-aromatization (RRA) as the key steps. This method is based on allyl Grignard addition to isatin derivatives to provide smooth access to 2,2-diallyl 3-oxindole derivatives through a 1,2-allyl shift. The diallyl derivatives were used as RCM precursors to afford a novel class of spirocyclopentene-3-oxindole derivatives, which underwent a novel RRA reaction to afford carbazole derivatives. The synthetic sequence to carbazoles was shortened by combining the RCM and RRA steps in an orthogonal tandem catalytic process. The utility of this methodology was further demonstrated by the straightforward synthesis of carbazole alkaloids, including amukonal derivative, girinimbilol, heptaphylline, and bis(2-hydroxy-3-methylcarbazole).

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“…For biologically active compounds containing the acylamide system, see: Bennasar et al (2006); Ladziata et al (2006). For bond-length data, see: Gao et al (2007).…”

Section: Related Literaturementioning

confidence: 99%

2-(Benzo[d]thiazol-2-ylsulfanyl)-N-(6-methyl-2-pyridyl)acetamide

Zhao

Wang

et al. 2009

Acta Cryst E

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In the title compound, C15H13N3OS2, the pyridine ring and the benzo[d]thiazole unit subtend a dihedral angle of 57.7 (2)°. The length of the Csp 2—S bond [1.7462 (17) Å] is significantly shorter than that of the Csp 3—S bond [1.8133 (18) Å]. The crystal structure is stabilized by intramolecular N—H⋯N and intermolecular C—H⋯O and C—H⋯N hydrogen-bond interactions. Furthermore, C—H⋯π interactions stabilize the crystal packing.

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Sequential N-Acylamide Methylenation−Enamide Ring-Closing Metathesis: Construction of Benzo-Fused Nitrogen Heterocycles

Cited by 67 publications

References 41 publications

Mechanistic Analysis and Optimization of the Copper-Catalyzed Enantioselective Intramolecular Alkene Aminooxygenation

Mechanistic Analysis and Optimization of the Copper-Catalyzed Enantioselective Intramolecular Alkene Aminooxygenation

Synthesis of Carbazole Alkaloids by Ring‐Closing Metathesis and Ring Rearrangement–Aromatization

2-(Benzo[d]thiazol-2-ylsulfanyl)-N-(6-methyl-2-pyridyl)acetamide

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