On Stevens' tropolone synthesis; hydrolysis of spirocyclopentadiene– and spiroindene–dichloroketen adducts

Tsunetsugu, Josuke; ASAI, M.; Hiruma, Sadao; Kurata, Yumiko; Mori, A.; ONO, K.; Satô, Masaru; Ebine, Seiji

doi:10.1039/p19830000285

Cited by 11 publications

(5 citation statements)

References 11 publications

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“…[62] O-Neopentyl xanthates are much less susceptible to ionic decomposition and were found more suitable. We later found a simple solution to this problem by studying earlier work in this area, [95][96][97][98][99][100][101][102][103][104][105][106] especially by Hassner and coworkers. [95 -101] α-Halocyclobutanones can be converted into oxyallyl cation (or equivalent) upon treatment with base, and these react readily with nucleophiles at both extremities, as shown in structure 231 (Scheme 34).…”

Section: An Alliance With the Horner -Wadsworth-emmons Condensationmentioning

confidence: 99%

Radical Alliances: Solutions and Opportunities for Organic Synthesis

Zard

2019

Helvetica Chimica Acta

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The present account discusses in detail various mechanistic features of the degenerative radical addition‐transfer of xanthates and related thiocarbonylthio congeners and makes a comparison with the more classical Kharasch reactions to which it is similar in certain aspects. The xanthate group reacts reversibly with the ‘active’ radicals in the medium and is able to store them in a somewhat inactive form. This increases their effective lifetime in the medium and, at the same time, lowers their absolute concentration while regulating their relative concentration. These properties translate into a powerful carbon–carbon bond forming process, especially as regards intermolecular additions to electronically unbiased (‘unactivated’) alkenes. Most functional groups are tolerated, in particular polar functions that often require protection with other chemistries. This broad versatility is illustrated by examples where the xanthate addition to the alkene is combined with other, more classical reactions to provide a convergent, rapid access to a wide range of useful structures. Emphasis has been placed on the synthesis of open chain and more complex carbocycles, as well as on the transfer of chirality. These ‘radical alliances’ include organosilicon chemistry, the Diels–Alder cycloaddition and cheletropic extrusion of sulfur dioxide, the Claisen sigmatropic rearrangement, and the Horner–Wadsworth–Emmons (HWE) condensation.

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Section: An Alliance With the Horner -Wadsworth-emmons Condensationmentioning

confidence: 99%

Radical Alliances: Solutions and Opportunities for Organic Synthesis

Zard

2019

Helvetica Chimica Acta

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“…acid system afforded only the triacetate (16) (13.3%). (19).-To a well stirred solution of the dione (2) (200 mg, 0.962 mmol) in dioxane ( 3 ml) was added I M aqueous sodium hydroxide (3 ml) dropwise during 30 min and the mixture was acidified with 10% sulphuric acid. The precipitates were extracted with ether (300 ml) and the extract was dried (MgS04).…”

Section: -Chlorocyclohepta[de]naphthalene-78-dione (9)-amentioning

confidence: 99%

“…The precipitates were extracted with ether (300 ml) and the extract was dried (MgS04). After removal of the solvent the residue was recrystallized from methanol to give the acid (19) (158 mg, 23%) as brownish yellow fine needles, m.p.…”

Section: -Chlorocyclohepta[de]naphthalene-78-dione (9)-amentioning

confidence: 99%

Synthesis and properties of cyclohepta[de]naphthalene-7,8-dione, o-pleiadienequinone

Tsunetsugu¹,

Kanda²,

Takahashi³

et al. 1984

J. Chem. Soc., Perkin Trans. 1

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Cyclohepta [de] naphthalene-7,8-dione, o-pleiadienequinone (2), was synthesized by hydrolysis of the acenaphthylene-dichloroketene adduct (5); chloro( hydroxy) ketone (6) was the precursor. Compound (2) afforded the triacetate (16) by a Thiele-Winter-type reaction and a phenalene compound (19) by alkaline hydrolysis. Spectral data suggest that the dione (2) has contributions from such canonical forms as 2,3-(2a) and/or 4,5benzotropolonate (2b) structures. The polarographic €+ value of the dione (2) is -0.23 V at pH 5.28 which is between that of 1,2-naphthoquinone and anthraquinone.Non-benzenoid quinones can be classified into three categories; diones with peripheral conjugation, diones without peripheral but with cross-conjugation, and fulvalenediones.? Although many non-benzenoid quinones belonging to the first category ([4n + 21 or [4n]annulenediones) have been reported, not many quinones belonging to the second or third categories are known. Belonging to the first category$ are cyclobutene-1,2-dione,' cyclo-octadecatetraenetetrayne-1,6-and -1,lOdione,2 1,6:8,13-propanediylidene[ 14]annulene-2,3-and -2,5d i ~n e , ~ 2,5,7-cyclo-octa-2,5,7-triene-1,4-4 and -1,2-dione,' 2,3,6,7-dibenzobicyclo[6.2.O]deca-2,6,8-trien-4-yne-9,l0-dione and 2,3:6,7-di benzo bicyclo [6.2.0]deca-2,4,6,8( 1)-tetraene-9, lOdione,6 8,9,4dione,,S-di0ne,~ azulene-1,2diones,' azulene-1,5-and -1,7-dione,' and acepleiadylene-5,6and 5,8-dione; ' ' belonging to the second are acenaphthenequinone (1) and cyclohepta[de]naphthalene-7,s-(2) and -7,lO-dione (3); l 3 belonging to the third are sesquifulvalene-7,10-dione,14 heptatriafulvalene-3,4-,'' and -1,2-dione,16 and heptafulvalene-3,4-dione.

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“…The quinone (5) was synthesized (62% yield) by hydrolysis of the dichloro ketene adduct (2) to give the acenaphthylene (1) using silver acetate in acetic acid as reported earlier;' an increased yield was obtained by increasing the quantity of reagent used in a slightly modified procedure. A small amount of the chloro acetoxy ketone (6) was also obtained as a minor product (0.6% yield); this shows characteristic absorption in its i.r.…”

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confidence: 99%

“…It is interesting to note that the concurrent formation of unusual bridgehead cations (3a) and (3b) in acidic conditions seems to be implied in this experiment; the acetate (4) was not isolated but its intermediate formation is supported by a number of many related facts. ' e 2 When the quinone (5) is allowed to react with an excess of various primary and secondary alcohols in the presence of an organic or Lewis acid with or without benzene as solvent, 8,8-dialkoxy ketones (7) and an isomeric mixture of 1-, 3-, and 6alkoxy quinones (8) were obtained (Scheme 2); the results are listed in Table 1. Some physical characteristics and the results of elemental analysis of the acetals (7) and the quinones (8) are given in Tables 2 and 3.…”

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confidence: 99%

o-Pleiadienequinones. Part 2. Nucleophilic substitution reaction of o-pleiadienequinone with alcohols

Tsunetsugu¹,

Yamaguchi²,

Ebine³

et al. 1986

J. Chem. Soc., Perkin Trans. 1

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In the course of the synthesis of the title compound (5) by the hydrolysis of the dichloro ketone (2) the acetoxy chloro ketone (6) was formed and accounted for in terms of the unusual bridgehead cation (3b). The nucleophilic substitution reaction of the compound (5) with various alcohols afforded alkoxy quinones (8) and/or acetals (7). The mechanism of the formation is discussed. The full characterization

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On Stevens' tropolone synthesis; hydrolysis of spirocyclopentadiene– and spiroindene–dichloroketen adducts

Cited by 11 publications

References 11 publications

Radical Alliances: Solutions and Opportunities for Organic Synthesis

Radical Alliances: Solutions and Opportunities for Organic Synthesis

Synthesis and properties of cyclohepta[de]naphthalene-7,8-dione, o-pleiadienequinone

o-Pleiadienequinones. Part 2. Nucleophilic substitution reaction of o-pleiadienequinone with alcohols

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