Methylenecyclopropane as an alkene component in the Khand-Pauson reaction

Smit, W. A.; Kireev, S. L.; Нефедов, О. М.; Тарасов, В. А.

doi:10.1016/s0040-4039(00)99313-4

Cited by 65 publications

(24 citation statements)

References 9 publications

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“…6).s5 The Pauson-Khand coupling between 20 and the cobalt complex derived from TMS-acetylene afforded 21 which upon further manipulation, yielded 22. Toral Synthesis of (13Z)-Spata-13,(15), 17-diene(22) …”

mentioning

confidence: 99%

The Asymmetric Pauson-Khand Reaction. A Review

Ingate

Marco-Contellers

1998

Organic Preparations and Procedures International

109

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mentioning

confidence: 99%

The Asymmetric Pauson-Khand Reaction. A Review

Ingate

Marco-Contellers

1998

Organic Preparations and Procedures International

109

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“…420,Université de Paris-Sud, complexes of acetylene. [10] [11] Most of these reactions have 91405 Orsay, France been reported to occur both inter-and intramolecularly.…”

Section: Intramolecular Cycloaddition/rearrangement Processmentioning

confidence: 99%

Intramolecular Cycloaddition/Rearrangement of Alkylidenecyclopropane Nitrones from Palladium(0)-Catalyzed Alkylation of Amino Acid Derivatives

Ferrara¹,

Cordero²,

Goti³

et al. 1999

Eur. J. Org. Chem.

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“…From the preparative point of view, PKRs of such alkenes offer a convenient synthetic approach to cyclopentenones containing fused (PKR of 1 ),7 spiro‐linked (PKR of 2 )1 and simultaneously fused and spiro‐attached (PKR of 3 ) cyclopropane moieties. Surprisingly, after the first examples of intermolecular9 and intramolecular1 PKRs of 2 , only a few more cases for reactions of 2 7b, 10 and none for 3 and their derivatives have been published during the last decade. This contribution summarizes our results in this area, most of which were obtained after our preliminary communications 1.…”

Section: Introductionmentioning

confidence: 99%

Intramolecular Pauson–Khand Reactions of Methylenecyclopropane and Bicyclopropylidene Derivatives as an Approach to Spiro(cyclopropanebicyclo[n.3.0]alkenones)

Meijere¹,

Becker²,

Stolle³

et al. 2005

Chemistry A European J

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The trimethylsilyl-protected enynes 9a-c and 14a,b with alkynyl substituents on the three-membered ring or on the double bond of a methylenecyclopropane or a bicyclopropylidene moiety were prepared in two steps from the alcohols 6a-c and 12a,b, respectively, by conversion to the iodides and their coupling with lithium (trimethylsilyl)acetylide (8) in 38-73% overall yields. The bicyclopropylidene derivative 9d was synthesized in 49% yield directly from bicyclopropylidene (3) by lithiation followed by coupling with (5-iodopent-1-ynyl)trimethylsilane (11). Enynes 9b-d were protiodesilylated by treatment with K2CO3 in methanol to give the corresponding unprotected enynes 10b-d in 53, 74 and 94% yield, respectively. Enynes 17a-c with a carbonyl group adjacent to the acetylenic moiety were synthesized from oxo derivatives 15a-c by Wittig olefination followed by coupling with 8 in 47, 18 and 12% overall yield, respectively. Pauson-Khand reactions of the methylenecyclopropane derivatives with a substituent on the ring (9a,b and 10a) as well as on the double bond (14a,b and their in situ prepared protiodesilylated analogues) proceeded smoothly by stirring of the corresponding enyne with [Co2(CO)8] in dichloromethane at ambient temperature followed by treatment of the formed complexes with trimethylamine N-oxide under an oxygen atmosphere at -78 degrees C to give tricyclic or spirocyclopropanated bicyclic enones 18a,b, 19a, 20a,b, 21a,b in good yields. Alkynylbicyclopropylidene derivatives 9c,d and 10c,d formed the corresponding cobalt complexes at -78 to -20 degrees C. Treatment of the latter with N-methylmorpholine N-oxide under an argon atmosphere at -20 degrees C gave the spirocyclopropanated tricyclic enones 18c, 19c and 18d in 31-45% yields. The structure of 19c was proved by X-ray crystal structure analysis. The cyclization of enynones 17a-c in MeCN at 80 degrees C gave the spirocyclopropanated bicyclic diketones 22a-c in 38-65% yields. Intramolecular PKRs of the enynes 25a,d with a chiral auxiliary adjacent to the triple bond gave the corresponding products 26a,d in 70 and 79% yield, respectively, as 5:1 and 8:1 mixtures of diastereomers, respectively. Addition of lithium dimethylcuprate or higher order cuprates to the double bond of the former furnished bridgehead-substituted bicyclo[3.3.0]octanones 27a-c in 57-86% yields. Protiodesilylation of 27a followed by acetal cleavage gave the enantiomerically pure spirocyclopropanated bicyclo[3.3.0]octanedione (1R,5R)- 29a with [alpha]D(20)=-148 (c=1.0 in CHCl3) in 55% overall yield.

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Methylenecyclopropane as an alkene component in the Khand-Pauson reaction

Cited by 65 publications

References 9 publications

The Asymmetric Pauson-Khand Reaction. A Review

The Asymmetric Pauson-Khand Reaction. A Review

Intramolecular Cycloaddition/Rearrangement of Alkylidenecyclopropane Nitrones from Palladium(0)-Catalyzed Alkylation of Amino Acid Derivatives

Intramolecular Pauson–Khand Reactions of Methylenecyclopropane and Bicyclopropylidene Derivatives as an Approach to Spiro(cyclopropanebicyclo[n.3.0]alkenones)

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