A versatile synthesis of butenolides total synthesis of (+/-)-mintlactone

Cory, Robert M.; Ritchie, Brian M.; Shrier, A. M.

doi:10.1016/s0040-4039(00)97172-7

Cited by 41 publications

(10 citation statements)

References 14 publications

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“…Ethyl 3-methyl-3-butenoate may be prepared by a number of methods, including deconjugation of ethyl 3-methyl-2-butenoate, 18 palladium-catalyzed alkoxycarbonylation of methallyl acetate, 19 and Fischer esterification of the corresponding carboxylic acid. Ethyl 3-methyl-3-butenoate may be prepared by a number of methods, including deconjugation of ethyl 3-methyl-2-butenoate, 18 palladium-catalyzed alkoxycarbonylation of methallyl acetate, 19 and Fischer esterification of the corresponding carboxylic acid.…”

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confidence: 99%

Chloroperoxidase as Enantioselective Epoxidation Catalyst: An Efficient Synthesis of (R)-(−)-Mevalonolactone

1996

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As an important intermediate in biosynthetic pathways leading to sterols, terpenes, corotenoids, and other pentanoid compounds, 1 (R)-(-)-mevalonic acid or especially its lactone form (4) has been a synthetic target of considerable interest. A number of chemical methodologies have been described, the most popular of which involves asymmetric induction provided by Sharpless epoxidation of a suitable allylic alcohol. 2 Chiral pool chemistry has been employed, either as chiral auxiliary 3 or as reagent 4 or involving Seebach's "self-reproduction of stereogenic centers". 5 Other interesting methodologies include the use of a chiral sulfoxide 6 and axially dissymmetric binaphthyldiamines, 7 although in these two cases the resulting ee was relatively low.Enzymes have been quite useful for the preparation of (R)-mevalonolactone. Lipase-catalyzed kinetic resolutions 8 and esterase hydrolysis of a prochiral diester 9 have proven effective. Attempts to oxidize a triol with either Gluconobacter sp. 10 or horse liver alcohol dehydrogenase 11 have generated the (S)-lactone.Considering the complexity and probable expense of many of these procedures, and given the high enantioselectivities observed with chloroperoxidase-catalyzed epoxidation of methallyl-type substrates, 12 we envisioned a concise route to (R)-mevalonolactone (4) as illustrated below. Table 1 lists 3-methyl-3-butenol and five derivatives. Each was tested for enantioselective epoxidation using chloroperoxidase 13 and tert-butyl hydroperoxide as terminal oxidant. The alcohol (entry 6) was recovered unchanged. 14 Moderate facioselectivity observed with the acetate (entry 4) was surprising when compared to far higher selectivity as seen with the reversed ester (entry 1) and with methallyl propionate 12 (94% ee). Each posseses essentially the same molecular length, though the distance between the olefinic and carbonyl moieties is different. How this relates to enantiomer distribution in the active site of chloroperoxidase is currently being investigated in our laboratories.The substrate providing superior enantioselectivity (entry 1) was epoxidized at a 3.0 mmol scale using 2.0 equiv of tert-butyl hydroperoxide and 0.014 mol % chloroperoxidase in 45 mL citrate buffer at rt (Scheme 1). Epoxide 1 was isolated in 67% distilled yield 15 and having an ee of 93%. Hydrocyanation of 1 occurred in 90% yield with no evidence of the other regioisomer. Chemoselective reduction of the cyano ester 2 with sodium borohydride in ethanol 16 produced mevalononitrile (3, 98%) which was hydrolyzed and lactonized (81%) to (R)mevalonolactone (4). 17 The entire sequence was repeated but without purification of any intermediates providing (R)-mevalonolactone in 57% overall yield and identical purity. † Dedicated to Professor Emeritus Nelson J. Leonard on the occasion of his 80th birthday.(1) Recent reviews concerning the discovery and role of mevalonate: Goldstein, J. L.; Brown, M. S.(13) Chloroperoxidase (EC 1.11.1.10) is commercially available from Sigma Chemical Co. or Chirazyme Laborato...

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confidence: 99%

Chloroperoxidase as Enantioselective Epoxidation Catalyst: An Efficient Synthesis of (R)-(−)-Mevalonolactone

1996

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“…A slight increase in the 1:2 ratio was achieved, although with lower overall yield, by epoxidation of 35, followed by in situ opening of the epoxide and acid lactonization (Scheme 16). In 1990, Cory et al 23 obtained 1 in a highly diastereoselective fashion, employing a sequence similar to that already described by Fujita et al 22 Chavan et al 24 Using the same protocol, the authors 24 also prepared other butenolides, the natural sesquiterpenes heritol 40 26 and heritonin 41, 27 both were prepared as a mixture with their isomers (3:2) ( Figure 2). A very similar sequence of reactions was employed by Lohray et al 25 The authors performed the kinetic resolution of the olefin 42, prepared from 34, and obtained the R isomer in 85% ee.…”

Section: Scheme 15mentioning

confidence: 92%

“…were developed in different years by Fujita et al, 22 Cory et al, 23 Chavan et al, 24 and Lohray et al 25 In the first route, 22 the acid 35, obtained in two steps from 34, was converted into a mixture of 1 and 2 (46:54 ratio) by iodolactonization followed by in situ dehydroiodination (Scheme 14). Analytical samples of 1 and 2 were obtained by column chromatography.…”

Section: From 4-methyl Cyclohexanonementioning

confidence: 99%

Syntheses of Mintlactone and Isomintlactone

Ferraz¹,

Longo²,

Grazini³

2002

Synthesis

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“…GC analyses were performed on a Hewlett-Packard 5890 instrument using the following capilary columns: HP-5 (Crosslinked Phenyl Methyl Silicone) 30 m × 0.53 mm × 0.88 µm; Ultra-1 (Crosslinked Methyl Silicone Gum) 25 m × 0.32 mm × 0.17 µm; CP-Cyclodextrin-B-2,3,6-M-19, 25 m × 0.25 mm × 0.25 µm; and Chirasil-Val-L, 25 m × 0.25 mm × 25 µm. 1 H NMR spectra were recorded at 300 MHz using CDCl 3 solutions with TMS as an internal standard on a Bruker Avance DRX 300 spectrometer. IR spectra were determined with a Specord M-80 infrared spectrophotometer (Carl Zeiss, Jena, Germany).…”

Section: Materials and Methods Analysismentioning

confidence: 99%

“…Epoxy esters seem to be the best substrates for these syntheses. [1][2][3][4] We applied many acidic agents for the induction of the lactonization process. Racemic epoxy esters afforded mixtures of racemic ␦-hydroxy-␥-lactones and ␥-hydroxy-␦-lactones.…”

mentioning

confidence: 99%

Lactones. 6. Microbial lactonization of γ,δ‐epoxy esters

Olejniczak¹,

Gawroński

Wawrzeńczyk³

2001

Chirality

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The ability of 19 microorganisms to perform the enantioselective lactonization of racemic gamma,delta-epoxy ester 3a and its 7-methyl homolog 3b was checked. It was found that Rhodotorula rubra preferentialy transformed both substrates to (-)-enantiomers of trans delta-hydroxy-gamma-lactones with ee 76% for 3a and 24% for 3b. The best efficiency (20-30%) and enantioselectivity (ee 60-100%) of formation of (-)-gamma-hydroxy-delta-lactones 6a and 6b was observed for lactonization by Botrytis cinerea and Fusarium semitectum, respectively.

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A versatile synthesis of butenolides total synthesis of (+/-)-mintlactone

Cited by 41 publications

References 14 publications

Chloroperoxidase as Enantioselective Epoxidation Catalyst: An Efficient Synthesis of (R)-(−)-Mevalonolactone

Chloroperoxidase as Enantioselective Epoxidation Catalyst: An Efficient Synthesis of (R)-(−)-Mevalonolactone

Syntheses of Mintlactone and Isomintlactone

Lactones. 6. Microbial lactonization of γ,δ‐epoxy esters

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