Catalytic, Interrupted Formal Homo-Nazarov Cyclization with (Hetero)arenes: Access to α-(Hetero)aryl Cyclohexanones

Williams, Corey W.; Shenje, Raynold

doi:10.1021/acs.joc.6b01312

“…The title compound was prepared from L23 (107 mg, 0.5 mmol) and tosyl chloride (105 mg, 0.55 mmol) according to a literature procedure. 8 Purification using silica gel column chromatography with 1:1 hexanes:EtOAc as the eluent gave the product as a colorless oil (184 mg, 78% yield). 1 H NMR (600 MHz, CDCl 3 ) δ 7.99 (d, J = 8.3 Hz, 1H), 7.76 (d, J = 8.4 Hz, 2H), 7.54 (dt, J = 7.8, 0.9 Hz, 1H), 7.40 (d, J = 1.1 Hz, 1H), 7.34 (ddd, J = 8.3, 7.2, 1.2 Hz, 1H), 7.28-7.21 (m, 3H), 4.45 (ddddd, J = 9.7, 8.5, 7.2, 5.0, 1.3 Hz, 1H), 4.19 (dd, J = 9.4, 8.6 Hz, 1H), 3.91 (dd, J = 8.5, 7.2 Hz, 1H), 3.12 (ddd, J = 14.8, 4.9, 1.2 Hz, 1H), 2.75 (ddd, J = 14.8, 8.6, 0.8 Hz, 1H), 2.36 (s, 3H), 1.97 (d, J = 1.2 Hz, 3H); The title compound was prepared from L23 (107 mg, 0.5 mmol) and 1,3-di-tert-butyl-5iodobenzene 11 (237 mg, 1.5 mmol) according to a literature procedure.…”

Section: (S)-2-methyl-4-((1-tosyl-1h-indol-3-yl)methyl)-45-dihydrooxa...mentioning

confidence: 99%

Directed, Palladium(II)-Catalyzed Enantioselective anti-Carboboration of Alkenyl Carbonyl Compounds

Liu¹,

Li²,

Zhang³

et al. 2019

Preprint

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A substrate-directed enantioselective <i>anti</i>-carboboration reaction of alkenes has been developed, wherein a carbon based nucleophile and a boron moiety are installed across the C=C bond through a 5- or 6-membered palladacycle intermediate. The reaction is promoted by a palladium(II) catalyst and a mondentate oxzazoline ligand. A range of enantioenriched secondary alkylboronate products were obtained with moderate to high enantioselectivity that could be further upgraded by recrystallization. This work represents a new method to synthesize versatile and valuable alkylboronate building blocks. Building on an earlier mechanistic proposal by Peng, He, and Chen, a revised model is proposed to account for the stereoconvergent nature of this transformation.

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“…Williams et al . reported on the homo ‐Nazarov reaction of donor–acceptor cyclopropanes 169 followed by trapping with various activated aromatic (heteroaromatic) nucleophiles giving cyclohexenols 170 (Scheme ).…”

Section: Interrupted Nazarov‐type Reactionmentioning

confidence: 99%

Recent Advances in the Interrupted Nazarov Reaction

Yadykov

¹

,

Ширинян

²

2019

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In recent decades there have been significant improvements in the efficiency of synthesis as a result of considerable progress in tandem reactions, cascade transformations and related one‐pot processes. These methodologies are less time‐consuming, more cost‐effective, and produce less waste compared to the classical stepwise protocols. The Nazarov cyclization is an important and versatile method for the synthesis of five‐membered carbocycles which are found in many natural compounds and functional molecules. Current activities in the field of the Nazarov reaction are focused on development of better catalysts, asymmetric options and increasing the efficiency of synthesis. This transformation is suitable for applying to an intensified step‐economy in interrupted versions and one‐pot protocols. Interrupted Nazarov reactions in particular take advantage of the stereospecific nature of the electrocyclization. The universality of these reactions has facilitated an access to a plethora of complex small molecules of high medicinal relevance. In this review, we present a comprehensive summary of recent advances in the interrupted Nazarov‐type cyclization, and classify these reactions according to the structure of the substrate or the reaction mechanism. This is the first review that presents a survey on various types of interrupted Nazarov cyclization and deals with the recent advances, especially using tandem/domino or one‐pot reaction strategies and covers the literature from 2009 to 2019.

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“…The title compound was prepared from L23 (107 mg, 0.5 mmol) and tosyl chloride (105 mg, 0.55 mmol) according to a literature procedure. 8 Purification using silica gel column chromatography with 1:1 hexanes:EtOAc as the eluent gave the product as a colorless oil (184 mg, 78% yield). 1 H NMR (600 MHz, CDCl 3 ) δ 7.99 (d, J = 8.3 Hz, 1H), 7.76 (d, J = 8.4 Hz, 2H), 7.54 (dt, J = 7.8, 0.9 Hz, 1H), 7.40 (d, J = 1.1 Hz, 1H), 7.34 (ddd, J = 8.3, 7.2, 1.2 Hz, 1H), 7.28-7.21 (m, 3H), 4.45 (ddddd, J = 9.7, 8.5, 7.2, 5.0, 1.3 Hz, 1H), 4.19 (dd, J = 9.4, 8.6 Hz, 1H), 3.91 (dd, J = 8.5, 7.2 Hz, 1H), 3.12 (ddd, J = 14.8, 4.9, 1.2 Hz, 1H), 2.75 (ddd, J = 14.8, 8.6, 0.8 Hz, 1H), 2.36 (s, 3H), 1.97 (d, J = 1.2 Hz, 3H); The title compound was prepared from L23 (107 mg, 0.5 mmol) and 1,3-di-tert-butyl-5iodobenzene 11 (237 mg, 1.5 mmol) according to a literature procedure.…”

Section: (S)-2-methyl-4-((1-tosyl-1h-indol-3-yl)methyl)-45-dihydrooxa...mentioning

confidence: 99%

Directed, Palladium(II)-Catalyzed Enantioselective anti-Carboboration of Alkenyl Carbonyl Compounds

Liu

¹

,

Li

²

,

Zeng

³

et al. 2019

Preprint

View full text Add to dashboard Cite

A substrate-directed enantioselective <i>anti</i>-carboboration reaction of alkenes has been developed, wherein a carbon based nucleophile and a boron moiety are installed across the C=C bond through a 5- or 6-membered palladacycle intermediate. The reaction is promoted by a palladium(II) catalyst and a mondentate oxzazoline ligand. A range of enantioenriched secondary alkylboronate products were obtained with moderate to high enantioselectivity that could be further upgraded by recrystallization. This work represents a new method to synthesize versatile and valuable alkylboronate building blocks. Building on an earlier mechanistic proposal by Peng, He, and Chen, a revised model is proposed to account for the stereoconvergent nature of this transformation.

show abstract

Catalytic, Interrupted Formal Homo-Nazarov Cyclization with (Hetero)arenes: Access to α-(Hetero)aryl Cyclohexanones

Cited by 21 publications

References 52 publications

Directed, Palladium(II)-Catalyzed Enantioselective anti-Carboboration of Alkenyl Carbonyl Compounds

Directed, Palladium(II)-Catalyzed Enantioselective anti-Carboboration of Alkenyl Carbonyl Compounds

Recent Advances in the Interrupted Nazarov Reaction

Directed, Palladium(II)-Catalyzed Enantioselective anti-Carboboration of Alkenyl Carbonyl Compounds

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