Synthesis of dl-7,8-epialantolactone. A tandem SN2' dehydrobromination-organocuprate addition exemplified

Schultz, Arthur G.; Godfrey, Jollie D.; Arnold, Edward; Clardy, Jon

doi:10.1021/ja00499a038

Cited by 20 publications

(10 citation statements)

References 5 publications

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“…The ring systems of the synthetic 7,8-trans-fused epialantolactone show similar conformations (Schultz, Godfrey, Arnold & Clardy, 1979). The relative stereochemistry at C(10), C(7) and C(8) in the title compound is identical with the conformations observed in isoalantolactone (Schmalle, Schoppe et al, 1986) and in diepoxy-yomogin (Schmalle, Klupsch et aL, 1986), which is in accordance with the findings of Marshall, Cohen & Hochstetler (1966).…”

Section: Bond Lengths (A) and Angles (O) Of Alantolactonesupporting

confidence: 77%

Structure of 4β,10β-dimethyleudesma-5,11(13)-diene-7β-lactone (alantolactone)

Schmalle¹

1986

Acta Crystallogr C

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Section: Bond Lengths (A) and Angles (O) Of Alantolactonesupporting

confidence: 77%

Structure of 4β,10β-dimethyleudesma-5,11(13)-diene-7β-lactone (alantolactone)

Schmalle¹

1986

Acta Crystallogr C

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“…The extract was washed by brine, dried over anhydrous MgS04, and evaporated. The residue was crystallized from hexane to give the title alcohol 6 (13), 99 (27), 86 (100) and 53 (15). (20), 133 (25), 114 (29), 99 (22), 86 (loo), 71 (40), 60 (30) and 54 (40).…”

Section: Resultsmentioning

confidence: 99%

“…in CH,CI, (150 cm3) was refluxed under Ar for 7 h. The solution was cooled, and washed successively with 10% aq. Na,C03 and brine, dried over anhydrous MgSO,, and evaporated to give the keto aldehyde 13 (14).…”

Section: Resultsmentioning

confidence: 99%

“…The residue was treated with PTSA (400 mg) in wet T H F (20 cm3) for 44 h. To the mixture was added an excess of diazomethane in diethyl ether. The mixture was evaporated and the residue was chromatographed over SiO, (eluted with diethyl ether-hexane 1 : 1) to give the title ester 22 (610 mg, 55% from 6) as an oil (Found: M + , 294 (25), 217 (13), 161 (23), 145 (15), 133 (16), 121 (19), 105 (30), 99 (42), 91 (74), 88 (40), 81 ( 5 3 , 69 (52), 56 (67) and 53 (100).…”

Section: Methylmentioning

confidence: 99%

“…ClsH2203 requires M, 250.157); v,,,(KBr)/cm-' 3480, 1746 and 1665; 6,6. 13 (1 H, d, J 1.2), 5.59 (1 H,brd,J1.2),4.47(1H,ddd,J1.7,5.0and5.0),2.98(1H,m), 2.06 (1 H, dd, J 1.5 and 15.5), 1.35-1.94 (9 H, m), 1.21 (3 H, s), 1.13 (3 H, s) and 1.08 (1 H, dd, J2.5 and 13.0); 6, 170.6, 142.2, 120.0, 77.0, 71.2, 48.8, 44.4, 42.0, 41.5, 41.1, 32.5, 30.4, 24.9, 20.0 and 17.3; m/z 250 ( M + , 17%), 232 (42), 163 (71), 147 (25), 133 (28), 121 (47), 11 1 (35), 99 (51), 91 (76), 86 (58), 71 (76), 67 (58) and 53 (100).…”

mentioning

confidence: 99%

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Total synthesis of three eudesman-12,8-olides, (±)-isoalantolactone, (±)-dihydrocallitrisin and (±)-septuplinolide; structure revision of septuplinolide

Tada¹,

Yamada²,

Kanamori³

et al. 1993

J. Chem. Soc., Perkin Trans. 1

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Four eudesman-I 2,8-olidesr ( f ) -isoalantolactone, () -septuplinolide and its epimeric eudesmanolide at C-4 were synthesized stereoselectively via the route involving alkylation annulation of 2-methyl-3-furoic acid and oxidation of the furan ring. It was found that the structure of septuplinolide is the C -4 epimer of the reported structure.) -dihydrocallitrisin, ( Recently, manifoldly oxygenated eudesmanolides have been isolated from different plant sources, and have been shown a wide range of biological activity, such as allergenic agent, plantgrowth inhibitor, antibacterial agent and antitumour agent activity.Previously, we reported syntheses of several furanoeremophilanes which are natural perhydronaphthofurans, uiu the coupling of two fragments A and B by alkylation of 2,4-dimethyl-3-furoic acid.* Eudesmanolides are also popular natural perhydronaphthofuran derivatives whose common carbon skeleton has methyl groups at different positions from those in the furanoeremophilanes. We intended to synthesize various eudesmanolides by a similar synthetic route which includes alkylation-annulation of 2-methyl-3-furoic acid 1 and oxidation of a furan ring to a y-lactone ring." The relative stereochemistry of the y-lactone ring with the 10-Me group of isoalantolactone 2 ' ' is opposite to that of dihydrocallitrisin 3."313 Septuplinolide was isolated by Ober and Fischer in 1987 and the structure was proposed to be a eudesmanolide with structure 4.14 In our survey of eudesmanolides, the oxygen function of C-4 of eudesmanolides is bonded on the 4a side,2-7.1 5 -19 except for a fewThe spectral data of the synthesized compound 4, which has the proposed structure for septuplinolide, were apparently different from the reported data of septuplinolide." The difference in the 'H NMR spectra between the two compounds suggested that the correct structure of septuplinolide is the C-4 epimer 5 of the reported structure 4 for septuplinolide. We report here the stereoselective syntheses of four eudesman-12,8-olides, ( f )isoalantolactone 2,' ' ( k )-dihydrocallitrisin 3,". ( +)-septuplinolide l4 5 and the C-4 epimeric (+)-eudesmanolide 4 of 5, and the spectroscopic structural elucidation of septuplinolide (Scheme 1).

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