The orientation of the β-hydroxyl group controls the diastereoselectivity during the hydride reduction and Grignard reaction of inososes

Jagdhane, Rajendra C.; Patil, Madhuri T.; Shashidhar, Mysore S.

doi:10.1016/j.tet.2013.04.081

Cited by 8 publications

(6 citation statements)

References 52 publications

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“…Seven different inositol derivatives 13–19 were obtained from the four inososes 5–7 and 11 in a stereoselective way, thereby controlling the stereochemistry of a third stereocentre of the inositol frame. The results of the reduction reactions are in good agreement with what has been reported before on similar compounds [45]. The structure and stereochemistry of inositols 13–19 were confirmed by 1 H, 13 C and 2D NMR experiments directly or after per-acetylation of the reduction product and/or through comparison with previously reported compounds.…”

Section: Resultssupporting

confidence: 89%

“…In fact (Table 1), the substituents α to the keto function (2 and 6) and the axial OH in position 3 have always a cis orientation which would favour an equatorially directed anti reduction using NaBH 4 as a reducing reagent in an alcoholic solvent (condition A ). In particular, it has been proven that the axial OH group β to the keto function plays a fundamental role in directing the nucleophilic attack [45–47]. It has also to be mentioned that by changing the experimental conditions (temperature and alcoholic solvent) a different diastereoselectivity has been reported in the reduction of the same protected inosose [45,48].…”

Section: Resultsmentioning

confidence: 99%

“…In particular, it has been proven that the axial OH group β to the keto function plays a fundamental role in directing the nucleophilic attack [45–47]. It has also to be mentioned that by changing the experimental conditions (temperature and alcoholic solvent) a different diastereoselectivity has been reported in the reduction of the same protected inosose [45,48]. This highlights how subtle changes in the inosose structure and/or in the experimental conditions affect the stereo-outcome of the reduction.…”

Section: Resultsmentioning

confidence: 99%

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Useful access to enantiomerically pure protected inositols from carbohydrates: the aldohexos-5-uloses route

D’Andrea

Catelani

Guazzelli

et al. 2016

Beilstein J. Org. Chem.

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The intramolecular aldol condensation of aldohexos-5-ulose derivatives of the D-xylo and L-ribo stereoseries has been studied. Only one of the four possible inososes was isolated from both stereoseries in reasonable yields (30–38%). The results obtained, together with the previous findings for the L-arabino and L-lyxo stereoseries, allowed for the rationalisation of a mechanism of the reaction based on open-transition-state models and electron-withdrawing inductive effects. Complementary reductions of the intermediate inososes were possible by changing the reaction conditions, and two isomeric inositol derivatives were obtained with complete stereoselection from each inosose. The presented approach permits us to control the configuration of three out of the six stereocentres of the inositol frame and gives access to seven of the nine inositols. Noteworthy, for the D-xylo derivative, the two-step sequence (condensation followed by reduction with NaBH(OAc)3) represents the biomimetic synthesis of myo-inositol. Furthermore, the sugar-based pathway leads directly to enantiomerically pure selectively protected inositols and does not require any desymmetrisation procedure which is needed when myo-inositol and other achiral precursors are employed as starting materials. As an example of application of the method, the indirect selective protection of secondary inositols’ hydroxy functions, by placing specific protecting groups on the aldohexos-5-ulose precursor has been presented.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Useful access to enantiomerically pure protected inositols from carbohydrates: the aldohexos-5-uloses route

D’Andrea

Catelani

Guazzelli

et al. 2016

Beilstein J. Org. Chem.

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“…The mixture was separated by column chromatography to afford the pure myo - and scyllo -inositol derivatives in 58% and 30% yields, respectively. The selectivity of this reduction was lower compared to previously published results [ 43 ]. A diastereoisomeric ratio of 4:1 myo -8 / scyllo -8 was estimated by 1 H NMR when the same reduction was done in a dichloromethane/methanol mixture.…”

Section: Resultscontrasting

confidence: 78%

Diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues

Collet¹,

Chrétien²,

Chapleur³

et al. 2016

Beilstein J. Org. Chem.

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SummaryEfficient routes were developed for the diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues. The key steps of the synthesis were the easy accessibility of different types of arms in term of configuration (myo and scyllo), the linking method and length, which could modulate the biological properties. These inositol derivatives, bearing an arm terminated either with a hydroxy group or a fluorine atom, could be interesting candidates for diastereoisomeric intermediates and biological evaluations, especially for PET imaging experiments.

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“…In all three reductions using sodium borohydride, the substrates have an axial 3-benzyloxy substituent hindering one face of the carbonyl that has been shown to control inosose reduction. 39 It is likely that the reactive conformations match the conformations determined by NMR as the alternative conformers have either three or four unfavorable axial benzyloxy groups. Furthermore, the alternative conformers would still have one axial 3-benzyloxy substituent and an axial 2-hydroxy substituent that would direct hydride to the opposite face to that observed.…”

Section: ■ Results and Discussionmentioning

confidence: 96%

Synthesis of allo- and epi-Inositol via the NHC-Catalyzed Carbocyclization of Carbohydrate-Derived Dialdehydes

2014

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A synthesis of carbocyclic sugars from carbohydrate-derived dialdehydes using organocatalysis has been developed. Sorbitol, mannitol, and galactitol were converted via 1,6-tritylation, perbenzylation or permethylation, detritylation, and Swern oxidation into 2,3,4,5-tetra-O-alkyl-dialdoses that were cyclized via the benzoin reaction promoted by a triazolium carbene. Manno- and galacto-configured dialdehydes gave predominantly single inosose stereoisomers in up to 75% yield if the mixture was acetylated prior to isolation while the gluco-dialdehyde afforded a mixture of three stereoisomers in 61% overall yield. The inososes were stereospecifically reduced using sodium borohydride and then deprotected to give allo- and epi-inositol in good yield that confirmed the structural and stereochemical assignments.

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The orientation of the β-hydroxyl group controls the diastereoselectivity during the hydride reduction and Grignard reaction of inososes

Cited by 8 publications

References 52 publications

Useful access to enantiomerically pure protected inositols from carbohydrates: the aldohexos-5-uloses route

Useful access to enantiomerically pure protected inositols from carbohydrates: the aldohexos-5-uloses route

Diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues

Synthesis of allo- and epi-Inositol via the NHC-Catalyzed Carbocyclization of Carbohydrate-Derived Dialdehydes

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