Regio‐ and stereospecific synthesis of polysubstituted alkenes by carbozincation of acetylenic sulfones

Xie, Meihua; Gu, Xiaoxia; Wang, Jialiang; Zhang, Jinhua; Lin, Gaofeng; Wang, Shaowu

doi:10.1002/aoc.1508

Cited by 9 publications

(2 citation statements)

References 38 publications

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“…There is little information on carbanion nucleophiles for C-C bond formation in THF solvent, probably due to interference by polymerization among the addition intermediates and electrophile. An alternative zinc-copper bimetallic approach was recently reported at elevated temperatures [22]. To avoid this problem in our research group, a substrate sulfone was slowly added into a dilute solution (<5 mM) containing an excess amount of nucleophile (ca.…”

Section: Conjugate Addition To Acetylenic Sulfonesmentioning

confidence: 99%

Conjugate addition approach for natural product synthesis inspired by gibberellin and solanoeclepin A targets

Isobe

2013

Pure and Applied Chemistry

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Trimethylzincate is known to react through conjugate addition to α,β-unsaturated ketones, but adds much faster to α,β-unsaturated esters at low temperatures. Since the intermediate zinc enolate behaves differently from that of dimethylcuprate, it offers scope for application in a partial synthesis of gibberellin A 3 . A second example involving vinylsulfones having an oxygen atom on the γ-carbon strongly directs incoming nucleophiles in conjugate addition mode. Heteroatom-directed conjugate addition (HADCA) provides very reactive carbanion intermediates leading to cyclobutane ring formation, necessary for synthesis of solanoeclepin A. An alternative reaction for the four-membered carbocyclic ring closure was explored to make a bond formation between the propargylic cation of Nicholas type and allyltrimethylsilane nucleophile of Hosomi-Sakurai type. This method allowed a formation of tricyclo[5.2.1.0 1,6 ]decene framework.Scheme 1 Typical conjugate addition to unsaturated ketone followed by aldol reaction.Scheme 2 Mechanisms and intermediates of cuprate and zincate conjugate addition. Scheme 3 Trimethylzincate conjugate addition to unsaturated diester through a different nature in the enolate intermediate from cupper/lithium enolate. Scheme 4 Similar conjugate addition via acidic conditions [9,10]. Scheme 5 Competitive addition between enone 1 and en-diester 5 with trimethylzincate. Scheme 7 Diastereo-switching HADCA via αor β-chelation effects. Scheme 8 Enantio-switching HADCA via epimerization of C-alkynyl precursor. Scheme 10 Cyclobutane formation via epoxide exo-opening by a carbanion from HADCA. Scheme 11 Sulfone carbanion intermediate can open epoxide ring for cyclobutane ring formation.In fact, the [2,3]Wittig rearrangement was implemented in one-pot process after temporarily protecting the terminal acetylenic proton by trimethylsilyl group under the deprotonation conditions of the propargylic proton. This rearrangement of 58 is highly stereoselective to give a single isomer 57. Once M. ISOBEScheme 15 Stereochemical course of HADCA includes trans-addition from the chelation face, and the a-sulfonyl carbanion reverts back to the chelation face. Scheme 16Retrosynthesis of solanoeclepin A right segment tricyclo[5.2.1.0 1,6 ]decene framework under acidic condition. Scheme 17 Synthesis of solanoeclepin A right segment tricyclo[5.2.1.0 1,6 ]decene framework.

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Section: Conjugate Addition To Acetylenic Sulfonesmentioning

confidence: 99%

Conjugate addition approach for natural product synthesis inspired by gibberellin and solanoeclepin A targets

Isobe

2013

Pure and Applied Chemistry

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“…Many synthetic methodologies have been developed throughout the history of organic chemistry for an effective olefination such as the Wittig-type reactions, the Heck-type reactions, and olefin metathesis . Alternatively, the Negishi-type addition of various organometallic reagents to alkynes provided a versatile strategy for alkene synthesis . On the other hand, the cleavage of the C−H bond in aldehydes promoted by transition metal leads to acyl hydrido metal intermediates, which could undergo decarbonylation reactions or further reactions to generate carbonyl compounds .…”

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confidence: 99%

Ru-Catalyzed Decarbonylative Addition of Aliphatic Aldehydes to Terminal Alkynes

Guo

Wang

2010

Org. Lett.

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A novel method for the formation of isolated C=C bonds was developed via a ruthenium-catalyzed decarbonylative addition of aliphatic aldehydes and alkynes. An unprecedented complete switch of chemoselectivity from aromatic aldehydes to aliphatic aldehydes was observed simply by using tri(2,4,6-trismethoxyphenyl)phosphine as ligand. A synthesis by this method of an insect sex pheromone was demonstrated.

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Carbozincation Reactions of Carbon–Carbon Multiple Bonds

2015

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Regio‐ and stereospecific synthesis of polysubstituted alkenes by carbozincation of acetylenic sulfones

Abstract: a Tri-or tetrasubstituted alkenes with various substituents can be constructed regio-and stereospecifically by treatment of acetylenic sulfones with organozinc reagents in tetrahydrofuran followed by hydrolysis or coupling with halohydrocarbon.

Cited by 9 publications

References 38 publications

Conjugate addition approach for natural product synthesis inspired by gibberellin and solanoeclepin A targets

Conjugate addition approach for natural product synthesis inspired by gibberellin and solanoeclepin A targets

Ru-Catalyzed Decarbonylative Addition of Aliphatic Aldehydes to Terminal Alkynes

Carbozincation Reactions of Carbon–Carbon Multiple Bonds

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