Efficient Access to Bicyclo[4.3.0]nonanes: Copper‐Catalyzed Asymmetric Silylative Cyclization of Cyclohexadienone‐Tethered Allenes

He, Zhi‐Tao; Tang, Xiaoqi; Xie, Li‐Bo; Cheng, Maojie; Tian, Ping; Lin, Guo‐Qiang

doi:10.1002/anie.201508125

Cited by 92 publications

(29 citation statements)

References 74 publications

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“…Thist ype of stereo-preference was observedb yG reaneyo nas imilar substrate without the closed A-ring lactone. [10a] However,t reating 10 with 4-TMS-3-butynyl lithium [10a] led to undifferentiated addition to both carbonyls, whereas 4-TMS-3-butynyl Grignard reagent caused an unexpected ketone reduction.H ereafter,h omologation of 11 was effected under CrabbØ's condition, [21,22]…”

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confidence: 99%

Synthesis of (±)‐Merrilactone A by a Desymmetrization Strategy

Liu

Wang

2018

Chemistry A European J

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confidence: 99%

Synthesis of (±)‐Merrilactone A by a Desymmetrization Strategy

Liu

Wang

2018

Chemistry A European J

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“…One possible complication would be competitive boryl conjugate addition ( i → vi , Scheme ) . This is a more formidable chemoselectivity challenge compared to when an allenyl, an alkynyl or a styrenyl substrate is used because these latter species are either less hindered and/or more electrophilic (vs. a butadiene).…”

Section: Methodsmentioning

confidence: 99%

Catalytic Enantioselective Conjugate Additions of (pin)B‐Substituted Allylcopper Compounds Generated in situ from Butadiene or Isoprene

Meng

Torker

et al. 2016

Angewandte Chemie

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Multicomponent catalytic enantioselective transformations that entail the combination of butadiene or isoprene (common feedstock), an enoate (prepared in one step) and B 2 (pin) 2 (commercially available) are presented. These processes constitute an uncommon instance of conjugate addition of an allyl moiety and afford the desired products in up to 83% yield and 98:2 enantiomeric ratio. Based on DFT calculations stereochemical models and rationale for the observed profiles in selectivity are provided. Keywordsboron; conjugate additions; copper; enantioselective catalysis; synthesis Multicomponent catalytic transformations can convert readily accessible starting materials to substantially more complex molecules. [1] One desirable scenario would involve 1,3-dienes and especially butadiene, a common feedstock produced in more than 10 million tons per year worldwide. However, catalytic enantioselective reactions with these unsaturated hydrocarbons, the majority of which are cycloadditions, are limited in number. [2] There are only the seminal contributions of Krische [3] regarding coupling of butadiene with alcohols or aldehydes, and the disclosures on reactions of 1-substituted butadienes with aldehydes [4a] and combination of aryl-based reagents and sodium dimethylmalonate. [4b-c] Enantioselective processes have been recently developed that begin with the addition of a chiral Cu-B(pin) complex (pin = pinacolato) to an alkene, [5] affording organocopper species that may then react with another electrophile. Cu-based catalysts have accordingly been utilized to merge an allene and an aldehyde or ketone, [6] an allene and an allylic phosphate, [7] or an enyne and an aldehyde enantioselectively. [8] Related strategies, some with a Pd-based co-catalyst, entail the use of an aryl olefin and an aryl or benzyl halide (nonenantioselective) [9] or an allylic carbonate (enantioselective). [10] A catalytic process with butadiene, B 2 (pin) 2 and an enoate (Scheme 1) might be envisioned that constitutes enantioselective conjugate addition (ECA) of an allyl group, a class of Correspondence to: Amir H. Hoveyda. HHS Public Access Author ManuscriptAuthor Manuscript Author ManuscriptAuthor Manuscript valuable reactions that remains severely underdeveloped. [11] Further, the only reported multicomponent enantioselective conjugate additions [12] begin with initial addition to an alkynyl or alkenyl group followed by an intramolecular conjugate addition. [13] The envisioned sequence would commence with the conversion of a 1,3-diene to allylcopper species ii and iii [14] and then iv or v (α-vs. γ-addition). One possible complication would be competitive boryl conjugate addition (i → vi, Scheme 1). [15 ] This is a more formidable chemoselectivity challenge compared to when an allenyl, [6,7,13b] an alkynyl [13a] or a styrenyl [13] substrate is used because these latter species are either less hindered and/or more electrophilic (vs. a butadiene).Preliminary experiments with butadiene and phosphine or N-heterocyclic carbe...

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“…Inspired by recent progress in the copper(I)-catalyzed asymmetric transformations of 1,3-enynes to functional chiral allenes and our continuous interest in catalytic asymmetric desymmetrization of cyclohexadienone derivatives [38][39][40][41][42][43][44][45][46][47][48] , we envisioned that the key axially chiral allenylcopper intermediate T1, generated from the chemo-, regio-, and enantio-selective insertion of 1,3enyne to chiral copper hydride species, would be rapidly trapped by the intramolecular enones to yield the desired chiral exocyclic allenes 2 with hopefully high enantioselectivity and diastereoselectivity ( Fig. 2d).…”

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Copper(I)-catalyzed diastereo- and enantio-selective construction of optically pure exocyclic allenes

Tan

Wang

et al. 2020

Nat Commun

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Among about 150 identified allenic natural products, the exocyclic allenes constitute a major subclass. Substantial efforts are devoted to the construction of axially chiral allenes, however, the strategies to prepare chiral exocyclic allenes are still rare. Herein, we show an efficient strategy for the asymmetric synthesis of chiral exocyclic allenes with the simultaneous control of axial and central chirality through copper(I)-catalyzed asymmetric intramolecular reductive coupling of 1,3-enynes to cyclohexadienones. This tandem reaction exhibits good functional group compatibility and the corresponding optically pure exocyclic allenes bearing cis-hydrobenzofuran, cis-hydroindole, and cis-hydroindene frameworks, are obtained with high yields (up to 99% yield), excellent diastereoselectivities (generally >20:1 dr) and enantioselectivities (mostly >99% ee). Furthermore, a gram-scale experiment and several synthetic transformations of the chiral exocyclic allenes are also presented.

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Efficient Access to Bicyclo[4.3.0]nonanes: Copper‐Catalyzed Asymmetric Silylative Cyclization of Cyclohexadienone‐Tethered Allenes

Cited by 92 publications

References 74 publications

Synthesis of (±)‐Merrilactone A by a Desymmetrization Strategy

Synthesis of (±)‐Merrilactone A by a Desymmetrization Strategy

Catalytic Enantioselective Conjugate Additions of (pin)B‐Substituted Allylcopper Compounds Generated in situ from Butadiene or Isoprene

Copper(I)-catalyzed diastereo- and enantio-selective construction of optically pure exocyclic allenes

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