A New Synthesis of Lavandulol via Indium/Palladium-Mediated Umpolung of Vinyloxirane

Araki, Shuki; Kambe, Shinya; Kameda, Keiko; Hirashita, T.

doi:10.1055/s-2003-38057

Cited by 28 publications

(11 citation statements)

References 3 publications

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“…Alkyl-substituted allylic phosphates are suitable starting materials as well, underscored by the efficient and highly selective formation of 17 (>98% conv, 95% S N 2′, 92.5:7.5 er); subsequent treatment with MeLi delivered the tertiary alcohol, and concomitant removal of the acyl group revealed an irregular monoterpene derived from Artemisia annua L., from which the potent antimalarial artemisinin was isolated. 17 …”

Section: Resultsmentioning

confidence: 99%

A Broadly Applicable NHC–Cu-Catalyzed Approach for Efficient, Site-, and Enantioselective Coupling of Readily Accessible (Pinacolato)alkenylboron Compounds to Allylic Phosphates and Applications to Natural Product Synthesis

2014

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A set of protocols for catalytic enantioselective allylic substitution (EAS) reactions that allow for additions of alkenyl units to readily accessible allylic electrophiles is disclosed. Transformations afford 1,4-dienes that contain a tertiary carbon stereogenic site and are promoted by 1.0–5.0 mol % of a copper complex of an N-heterocyclic carbene (NHC). Aryl- as well as alkyl-substituted electrophiles bearing a di- or trisubstituted alkene may be employed. Reactions can involve a variety of robust alkenyl–(pinacolatoboron) [alkenyl–B(pin)] compounds that can be either purchased or prepared by various efficient, site-, and/or stereoselective catalytic reactions, such as cross-metathesis or proto-boryl additions to terminal alkynes. Vinyl-, E-, or Z-disubstituted alkenyl-, 1,1-disubstituted alkenyl-, acyclic, or heterocyclic trisubstituted alkenyl groups may be added in up to >98% yield, >98:2 SN2′:SN2, and 99:1 enantiomeric ratio (er). NHC–Cu-catalyzed EAS with alkenyl–B(pin) reagents containing a conjugated carboxylic ester or aldehyde group proceed to provide the desired 1,4-diene products in good yield and with high enantioselectivity despite the presence of a sensitive stereogenic tertiary carbon center that could be considered prone to epimerization. In most instances, the alternative approach of utilizing an alkenylmetal reagent (e.g., an Al-based species) represents an incompatible option. The utility of the approach is illustrated through applications to enantioselective synthesis of natural products such as santolina alcohol, semburin, nyasol, heliespirone A, and heliannuol E.

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Section: Resultsmentioning

confidence: 99%

A Broadly Applicable NHC–Cu-Catalyzed Approach for Efficient, Site-, and Enantioselective Coupling of Readily Accessible (Pinacolato)alkenylboron Compounds to Allylic Phosphates and Applications to Natural Product Synthesis

2014

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“…Koo et al [29] recently reported a stereoselective synthesis of S-8 from (R)-(-)-carvone (R-6) involving chemo selective but indirect deoxyg enation of allylic alcohol S-7 with retention of the homoallylic hydroxyl group (Scheme 7). Their method is superior in terms of ready availability of the starting material to other reported examples of racemic and stereoselective synthesis of lavandulol [28][29][30][31][32][33][34]. However, the key deoxygenation of S-7 to S-8 requires a tedious multi-step protection/deprotection sequence and stoichiometrically generates salt as a waste product [29].…”

Section: Application To (S)-(+)-lavandulol Synthesismentioning

confidence: 99%

Photocatalytic hydrogenolysis of allylic alcohols for rapid access to platform chemicals and fine chemicals

Takada

Caner

Naka

et al. 2017

Pure and Applied Chemistry

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Abstract:A brief account of our recent work on the chemo-, regio-and stereoselective photocatalytic hydrogenolysis of allylic alcohols to alkenes promoted by palladium-loaded titanium oxide (Pd/TiO 2 ) photocatalysts is presented. Since methanol is employed as the reducing agent, the method does not involve stoichiometric generation of salt waste. The photocatalytic hydrogenolysis proceeds at room temperature, and is compatible with the presence of functional groups such as C=C double bonds and hydroxyl groups at non-allylic positions. The regioselectivity is predictable: the hydrogen atom is predominantly incorporated into the sterically less hindered carbon atom of the allylic moiety. This protocol should provide straightforward green access to a range of platform chemicals (exemplified by the two-step synthesis of propylene from glycerol) and fine chemicals [e.g. (S)-(+)-lavandulol from (R)-(-)-carvone] without the need for protection/deprotection steps.

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“…The styrene epoxide and alkyl monosubsituted epoxides (17a) have undergone regioselective allylation with pregenerated allylindium reagent in dry THF to provide mixture of two possible homoallylic alcohols (18) and (19) with preferential nucleophilic attack at less substituted carbon (Scheme 5) [6]. In case of disubstituted terminal epoxides (17b) complete regioselectivity has been observed.…”

Section: Nucleophilic Additionsmentioning

confidence: 99%

“…The reaction has been extended to the synthesis of the lavandulol-a defensive pheromone of red lined carrion beetle and important constituent of perfume industry [19]. The coupling of isopropenyl oxirane (57b) and 3-methyl-but-2-enal (60) These reactions have demonstrated the umpolung of reactivity of aziridines as nucleophiles, which are conventially good electrophiles.…”

Section: Umpolung Of Reactivitymentioning

confidence: 99%

Indium Reagents in Heterocyclic Chemistry

Kumar

Kaur²,

Kumar

2005

COC

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Indium due to its moderate heterophilicity and recyclability plays significant role in indium catalyzed / mediated reactions of heterocycles. The co-ordination of hetero atom of the heterocycle with indium and the electronic contributions of heteroatoms in the ring provide more versatility in comparison to acyclic and carbocyclic systems. Here, the applications of indium reagents in heterocyclic chemistry have been reviewed. The review discusses the applications of indium salts -both inorganic and organometallics in the transformations of three, four, five and six membered heterocycles; synthesis of heterocycles through cycloaddition, cyclocondensation reactions, intramolecular cyclization, cascade reaction and heterocyclic modifications on the ring or on the appendage etc.

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A New Synthesis of Lavandulol via Indium/Palladium-Mediated Umpolung of Vinyloxirane

Abstract: A short synthesis of lavandulol is achieved by the In/Pdmediated reaction of isopropenyloxirane with 3-methylbut-2-enal.

Cited by 28 publications

References 3 publications

A Broadly Applicable NHC–Cu-Catalyzed Approach for Efficient, Site-, and Enantioselective Coupling of Readily Accessible (Pinacolato)alkenylboron Compounds to Allylic Phosphates and Applications to Natural Product Synthesis

A Broadly Applicable NHC–Cu-Catalyzed Approach for Efficient, Site-, and Enantioselective Coupling of Readily Accessible (Pinacolato)alkenylboron Compounds to Allylic Phosphates and Applications to Natural Product Synthesis

Photocatalytic hydrogenolysis of allylic alcohols for rapid access to platform chemicals and fine chemicals

Indium Reagents in Heterocyclic Chemistry

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