Total synthesis of stebisimine

Kametani, T.; Kusama, O.; Fukumoto, K.

doi:10.1039/c1967001212b

Cited by 7 publications

(10 citation statements)

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“…The resulting allylic alcohol (8) was oxidized with pyridinium chlorochromate to the enone (9) which was treated with a-lithio-a-methoxyallene, prepared in situ from methoxyallene6 with n-butyl-lithium, to give the 1,2-adduct (10). According to Magnus' p r ~c e d u r e , ~ the crude alcohol (10) was treated with potassium t-butoxide in the presence of 18-crown-6 to afford the cyclized enol ether (11) which was then, without isolation, hydrolysed with 6 ~hydrochloric acid to the desired ketone (12) [v,,,,(CHCl,) 1 743 cm ' 1 in 61% yield from (9). Introduction of two different dienophiles to the a position to the carbonyl group in (12) was accomplished by the procedure described as follows.…”

Section: A New Synthetic Approach T O Bruceantin Via An Intramolecula...mentioning

confidence: 99%

A new synthetic approach to bruceantin via an intramolecular Diels–Alder reaction: stereoselective construction of the pentacyclic model system

Shishido¹,

Saitoh²,

Fukumoto³

et al. 1984

J. Chem. Soc., Perkin Trans. 1

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Section: A New Synthetic Approach T O Bruceantin Via An Intramolecula...mentioning

confidence: 99%

A new synthetic approach to bruceantin via an intramolecular Diels–Alder reaction: stereoselective construction of the pentacyclic model system

Shishido¹,

Saitoh²,

Fukumoto³

et al. 1984

J. Chem. Soc., Perkin Trans. 1

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“…iV-(5-Benzyloxy-2-bromo-4-methoxyphenethyl)-4-methoxyphenylpropionamide ( 6). -To a mixture of 5-benzyloxy-2bromo-4-methoxyphenethylamine (4) (prepared from 3.72 g of its hydrochloride by the usual method), 15 ml of 5% sodium hydroxide, and 60 ml of chloroform was added dropwise a solution of 2.4 g of 4-methoxyphenylpropionyl chloride (5) in 20 ml of chloroform with stirring at 2-5°d uring 30 min; stirring was continued at 2-5°for 30 min and then at room temperature for 2 hr. The organic layer was separated, washed with 5% hydrochloric acid and water, dried over Na2S04, and evaporated in vacuo to give 3.93 g (81.3%) of the amide 6 as colorless needles (from benzene), mp 164-165°, ir (CHCh) 3380 and 1650 cm""1.…”

Section: Experimental Section13mentioning

confidence: 99%

Syntheses of heterocyclic compounds. CCCXCV. Synthesis of homopetaline-type compounds

Kametani¹,

Fukumoto²,

Fujihara³

1971

J. Org. Chem.

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extracted with ether. The extract was washed with sodium chloride solution, dried over K2C03, and distilled off to give 330 mg of a stereoisomeric mixture of amino ester 12 [ir (CHC13) 3450, 2900, 2750, 1720, and 1600 cm"1; m/e 300 (M+)], which was used in the following reaction without purification because of difficult crystallization.(±)-Isodasycarpidone ( 15) and (±)-Iso-5-epidasycarpidone (16).-A mixture of 300 mg of the amino esters 12,1 g of potassium hydroxide, 10 ml of water, and 20 ml of ethanol was refluxed for 5 hr. The resulting mixture was neutralized with concentrated hydrochloric acid and the solvent was evaporated completely to give a residue, which was extracted with dry ethanol.Removal of the extract gave 270 mg of 5-ethyl-4-hydroxycarbonyl-2-(3-indolyl)-l-methylpiperidine (14) as a powder, which was treated with polyphosphoric acid (prepared from 2 ml of phosphoric acid and 4 g of phosphorus pentoxide) at 90-95°for 1 hr. To the reaction mixture was added 5 ml of water, and the resulting mixture was basified with ammonia and extracted with ether. The extract was washed with sodium chloride solution, dried over K2C03, and distilled off to give 98 mg of a pale yellow syrup, whose preparative thick layer chromatography (ethyl acetate-benzene-methanol, 2:2:1) on silica gel afforded 16 mg of (± )-isodasyca,rpdione (15) and 9 mg of (± )-iso-3-epidasyc arpidone ( 16). Recrystallization of 15 from methanol-ether gave colorless needles: mp 220-221°; ir (CHCls) 3430, 2900, 2780, and 1645 cm-1; nmr

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“…Secondly, we investigated a direction of ring opening of the benzocyclobutene (11), in which two substituents located at the geminal position have a different bulkiness. The starting benzocyclobutene (11) is synthesized as follows.…”

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confidence: 99%

“…The starting benzocyclobutene (11) is synthesized as follows. Alkylation5 of the 1 -cyanobenzocyclobutene (4) with 6-chlorohexyl bromide in the presence of sodium amide, followed by a dehy-drochlorination5 of the resulting compound 10 with potassium tert-butoxide in dimethylformamide, afforded the 1,1-disubstituted benzocyclobutene 11 in 38.5% overall yield.…”

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confidence: 99%

Competitive reactions between sigmatropic reaction and cycloaddition affected by geometry of o-quinodimethanes

Kametani¹,

Tsubuki²,

Shiratori³

et al. 1977

J. Org. Chem.

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Total synthesis of stebisimine

Cited by 7 publications

References 0 publications

A new synthetic approach to bruceantin via an intramolecular Diels–Alder reaction: stereoselective construction of the pentacyclic model system

A new synthetic approach to bruceantin via an intramolecular Diels–Alder reaction: stereoselective construction of the pentacyclic model system

Syntheses of heterocyclic compounds. CCCXCV. Synthesis of homopetaline-type compounds

Competitive reactions between sigmatropic reaction and cycloaddition affected by geometry of o-quinodimethanes

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