W(CO)<sub>5</sub>(L)-Catalyzed Endo-Selective Cyclization of Allenyl Silyl Enol Ethers:  An Efficient Method for the Cyclopentene Annulation onto α,β-Unsaturated Ketones

Miura, Tomoya; Kiyota, Koichi; Kusama, Hiroyuki; Lee, Kooyeon; Kim, Hyun‐Seok; Kim, Sunggak; Lee, Phil Ho; Iwasawa, Nobuharu

doi:10.1021/ol034365a

Cited by 49 publications

(10 citation statements)

References 9 publications

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“…In addition, the use of TMSCl as reaction additive also effected the transformation with moderate to good performance . Interestingly, the resulting silyl enol ether products bearing a propargyl or allenyl substituent were able to undergo a W(CO) 5 (THF)- or W(CO) 5 -catalyzed intramolecular cyclization to give the corresponding cyclopentene derivatives in good yields. , …”

Section: Propargylindium and Allenylindium Reagentmentioning

confidence: 99%

Organoindium Reagents: The Preparation and Application in Organic Synthesis

et al. 2012

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allylation performed in aqueous media, an efficient synthesis of highly functionalized lactones was realized in good yields (64− 77%, Scheme 29). 238 However, the chirality installed during the first step almost had no influence on the second step, thus resulting in poor diastereoselectivity in the subsequent allylation reaction (1:1−2:1 dr).In situ formation of aldehyde from the oxidation of alcohol followed by one-pot indium-mediated allylation also provides an alternative method for the synthesis of homoallylic alcohol. Recently, Yadav and co-workers developed such a one-pot sequence by using chloramines-T (sodium salt of Nchlorotosylamide) as oxidant in the presence of a catalytic amount of FeCl 3 in CH 2 Cl 2 , giving rise to homoallylic alcohols in good to excellent yields (Scheme 30). 239 It is noteworthy that the generated byproduct of TsNH 2 (from the reduction of chloramines-T) may react with the in situ-formed aldehydes to give intermediates of N-tosylimines in the presence of 4 Å molecular sieve under refluxing; the thus-formed N-tosylimines subsequently underwent one-pot indium-mediated allylation to produce homoallylic amines in 60−80% yields. Later, a similar one-pot, two-step sequence for the synthesis of homoallylic alcohols via a galactose oxidase-mediated chemo-enzymatic oxidation of benzyl and cinnamyl alcohols to the corresponding Scheme 23 Scheme 24 Scheme 25 Scheme 26 Scheme 27 Scheme 28 Scheme 29 Scheme 30 Chemical Reviews Review dx.

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Section: Propargylindium and Allenylindium Reagentmentioning

confidence: 99%

Organoindium Reagents: The Preparation and Application in Organic Synthesis

et al. 2012

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“…Lee and Iwasawa et al reported that under the catalysis of W(CO) 6 (10 mol %) the allene moiety in 696 can undergo intramolecular endo -mode cyclization with the enol silyl ether moiety. Activation of the terminal CC bond in the allene moiety by the coordination with W(CO) 5 THF may direct the attack of the carbon nucleophile to form 699 , which upon protonolysis would afford 693 (Scheme ) 144 …”

Section: Nucleometalation Reactionsmentioning

confidence: 99%

Some Typical Advances in the Synthetic Applications of Allenes

2005

Chem. Rev.

1,353

256

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In 1989, Kakiuchi et al. reported that under irridation propadiene can undergo [2+2]-cycloaddition with R,β-unsaturated cyclohexenones to afford methylene-cyclobutane-containing bicyclic products 1 (Scheme 1). 6 Shi et al. reported that under the catalysis of DABCO, N-tosylated imines 2 can undergo [2+2]cycloaddition with 2,3-butadienoate or 3,4-pentadien-2-one to afford azetidine derivatives 3. 7 The reaction proceeded via the nucleophilic addition of DABCO to the electron-deficient allene forming 4-and 5-type intermediate, which may undergo 1,2-addition with the imines to afford 6. Intramolecular conjugate Scheme 1

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“…Other acyclic a,b-enones containing n-pentyl (entry 3), phenyl (entries 4 and 6), and 2-thienyl group (entry 5) underwent the Hosomi-Sakurai reaction with almost the same efficiency to afford the desired compounds in good yields. The conjugate addition of allyltrimethylsilane proceeded well in the case of cyclic a,b-enones (entries [7][8][9][10][11][12][13][14]. The reaction of 2-methylcyclopenten-1-one (8a) with allyltrimethylsilane gave 3-allyl-2-methylcyclopentanone (8b) (cis:trans, 1:1.3) in 81% yield (entry 8).…”

Section: Methodsmentioning

confidence: 99%

“…1 Recently, indium(III) chloride-mediated Hosomi-Sakurai reactions were reported. 3 Also, allylbarium, 4 allylcopper, 5 allylindium, 6 and allenylindium 7 have been developed to avoid strongly acidic conditions. The allylation of acyclic a,benones is far more difficult than that of cyclic a,b-enones with these reagents.…”

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confidence: 99%