Diastereoselective ring—opening of 12-acetoxy-9α and 9β(11)-epoxy-7-drimene: Homochiral semisynthesis of poligodial and warburganal

Urones, Julio G.; Marcos, Isidro S.; Gómez-Pérez, Belén; Lithgow, Anna M.; Dı́ez, David; Basabe, P.; Gómez, P. M.

doi:10.1016/s0040-4039(00)73098-x

Cited by 17 publications

(5 citation statements)

References 18 publications

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“…The stereochemistry of 34 was confirmed by the NOE enhancements observed between protons 12-H (irradiated) and CH 3 -10 and 7β-H. Attempts to transform 34 into hydroxy dialdehyde 35, a potential intermediate for 9α-fluoropolygodial, using several Swern oxidation conditions [53] only afforded complex reaction mixtures. Likewise, oxidation with some of the oxidizing reagents used for the oxidation of 1,4-diols to lactones did not give the hydroxy lactone 36, the 9α-fluoro analogue of the antifungal drimane peniopholide [54] and a potential intermediate for 9α-fluorocinnamolide, but instead afforded the regioisomeric lactone 37.…”

Section: Preparation Of Other 9α-fluorodrimanesmentioning

confidence: 92%

Preparation of 9α‐Fluorinated Sesquiterpenic Drimanes and Evaluation of Their Antifeedant Activities

Abad¹,

Agulló²,

Cuñat³

et al. 2010

Eur J Org Chem

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The preparation of 9α‐fluoro analogues of both natural and unnatural drimane‐type sesquiterpenes is described. Their synthesis began with the initial preparation of methyl 8‐keto‐12‐nordriman‐11‐oate from β‐ionone and entailed the electrophilic fluorination of C‐9 for the stereoselective introduction of the fluorine atom. The drimane skeleton was completed from the intermediate 9α‐fluoro‐8‐keto‐12‐nordrimane system by means of different reactions at the C‐8 ketone carbonyl group, essentially Wittig methylenation, cyanohydrin formation or palladium‐catalysed carbonylation of the corresponding enol triflate. Further manipulation of the functionalization derived from these key reactions allowed the preparation, among others, of 9α‐fluorodrimanes, which are structurally and functionally related to albicanic acid, drimenin and olepupuane. Also described are the reactivities of some of the fluorine‐containing systems prepared and a comparative study of the antifeedant activities of a selection of 9α‐fluorodrimanes and the corresponding hydrogen analogues against several insect species with different feeding ecologies (Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi), which revealed a significant increase in the antifeedant activities of some of the fluorinated drimane analogues.

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Section: Preparation Of Other 9α-fluorodrimanesmentioning

confidence: 92%

Preparation of 9α‐Fluorinated Sesquiterpenic Drimanes and Evaluation of Their Antifeedant Activities

Abad¹,

Agulló²,

Cuñat³

et al. 2010

Eur J Org Chem

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“…The stereochemistry assigned to the C-8 carbon was indirectly deduced from gs-sel-1 H 1D-NOESY correlations experiments; long range interactions between H-12α with H17b and H-17a with Me-20 were observed, therefore suggesting the stereochemistry at C-8 (see Figure 2b). Because under these conditions (K 2 CO 3 /MeOH) it was not possible to obtain the desired compound, we then focused on attempting the opening of the epoxide ring with HIO 4 , according to a method previously described for other oxirane rings [20,21]. Under these conditions, we hoped to generate a diol function between the C-8 and C-17 carbons, which by subsequent treatment with Pb(OAc) 4 in benzene [22], would give the desired ketone group at C-8.…”

Section: Resultsmentioning

confidence: 99%

Oxidative Degradations of the Side Chain of Unsaturated Ent-labdanes. Part II

et al. 2007

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Abstract:A route for the degradation of the side chain of ent-labdane derivatives has been devised, giving the useful synthon 2β, 12-dihydroxy-13,14,15,16,17-pentanor-ent-labdane-8-one (8). The use of this compound in the preparation of terpenylquinone derivatives shall be reported elsewhere. In addition we have synthesized the compound 2β,12-diacetoxy-8β,17-epoxy-13,14,15,16-tetranor-ent-labdane (10), which upon catalytic epoxide ring opening in alkaline or acid media gave rise in all cases to the formation of tricyclic compounds.

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“…The more common templates used for semisynthetic work are tricyclic diterpenoids such as (+)-abietic acid, (-)-levopimaric acid, podocarpic acid and bicyclic diterpenoids like manool, the communic acids, (-)-sclareol, (+)-cis-abienol, labdanolic acid, glycirretinic acid [11] and zamoranic acid [12][13]. Oxidative cleavage reactions of the side chain of communic acids with ozone and the OsO 4 -NaIO 4 system have been reported previously [14].…”

Section: Introductionmentioning

confidence: 99%