- Total synthesis of quercitols: (+)- allo -, (-)- proto -, (+)- talo -, (-)- gala -, (+)- gala -, neo -, and (-)- epi -quercitol
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The cyclohexenenones exo- and endo-2 were converted into the cyclohexenyl acetates exo- and endo-3 and exo- and endo-5 with a diastereoselectivity of >99:1 (2 steps). Ether cleavage with DDQ in CH2Cl2/H2O (20:1) and in situ ketal hydrolysis afforded the cyclohexenones 6 and 7 in up to 83% and 87% yield, respectively. Compound 6 was converted into (+)-allo- and (-)-proto-quercitol with a diastereoselectivity of 100:0 (4 steps). Moreover, 6 was carried on to (-)-talo-quercitol whereas 7 furnished the four remaining title quercitols (3-5 steps) including both enantiomers of gala-quercitol.
- Aucktor, Johannes,Brückner, Reinhard
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p. 250 - 258
(2015/03/05)
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- Stereoselective syntheses of racemic quercitols and bromoquercitols starting from cyclohexa-1,4-diene: Gala-, epi-, muco-, and neo-quercitol
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The efficient synthesis of gala-, epi-, neo-, and muco-quercitols and some brominated quercitols starting from cyclohexa-1,4-diene is reported. Treatment of the dibromide, obtained by the addition of bromine to cyclohexa-1,4-diene, with m-chloroperbenzoic
- Aydin, G?kay,Savran, Tahir,Akta?, Fatih,Baran, Arif,Balci, Metin
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p. 1511 - 1524
(2013/05/21)
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- Intramolecular hydrogen abstraction in radicals derived from inositol 1,3-acetals: Efficient access to cyclitols
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The benzylidene acetals obtained by cleavage of the orthobenzoate moiety in myoinositol 1,3,5-orthobenzoate were used to prepare mono- as well as di-deoxy inositol derivatives via their xanthates. The dideoxygenation is a result of intramolecular abstraction of the benzylidene acetal hydrogen and subsequent cleavage of the acetal ring. Such a cleavage does not take place in analogous acetals derived from, other orthoesters. The 1, 3-acetals derived from, myo- inositol 1,3,5-orthoesters were also used to prepare neo-inositol and isomeric deoxy-amino inositols. Most of the reactions in these synthetic sequences starting from myo-inositol give one product in each step. The results presented here show that myo-inositol 1,3,5-orthobenzoate offers many advantages over other orthoesters for the synthesis of cyclitol derivatives from myo-inositol.
- Murali, Chebrolu,Gurale, Bharat P.,Shashidhar, Mysore S.
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supporting information; experimental part
p. 755 - 764
(2010/03/26)
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- Highly stereoselective and stereospecific syntheses of a variety of quercitols from d-(-)-quinic acid
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The highly stereoselective synthesis of (-)-epi-, (-)-allo- and neo-quercitols as well as stereospecific synthesis of (-)-talo- and (+)-gala-quercitols have been achieved. The general strategy is employing dihydroxylation of the isolated double bond of various kinds of protected chiral (1,4,5)-cyclohex-2-ene-triols, which are derived from d-(-)-quinic acid. The choosing of protecting groups from either BBA (butane 2,3-bisacetal) or acetyl groups will result in the various degrees of stereoselectivity of dihydroxylation. On the other hand, the cyclohexylidene acetal moiety is attributed to the stereospecificity during dihydroxylation to afford the request molecules.
- Shih, Tzenge-Lien,Lin, Ya-Ling,Kuo, Wei-Shen
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p. 1919 - 1924
(2007/10/03)
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- An efficient and highly stereoselective synthesis of gala-Quercitol from 1,4-cyclohexadiene
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gala-Quercitol was synthesized from 1,4-cyclohexadiene in seven steps and overall yield of 68%. Reaction of 5,6-dibromo-2,2-dimethylhexahydro-1,3-benzodioxole, synthesized from 1,4-cyclohexadiene in three steps, with excess NaOMe gave (3aα,5α,7aα)-5-metho
- Baran, Arif,Secen, Hasan,Balci, Metin
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p. 1500 - 1502
(2007/10/03)
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- An Advantageous Synthesis of 1D- and 1L-1,2,3,5/4-Cyclohexanepentol
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The title compounds D-10 and L-10 were prepared from 1 in eight steps and in a combined overall yield of 41-49%.
- Biamonte, Marco A.,Vasella, Andrea
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p. 688 - 694
(2007/10/03)
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- A concise and convenient synthesis of DL-proto-quercitol and DL-gala-quercitol via ene reaction of singlet oxygen combined with [2 + 4] cycloaddition to cyclohexadiene
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Photooxygenation of 1,4-cyclohexadiene afforded hydroperoxy endoperoxides 3 and 4 in a ratio of 88:12. Reduction of 3 with LiAlH4 or thiourea followed by acetylation of the hydroxyl group and KMnO4 oxidation of the double bond gave proto-quercitol 10b. Application of the same reaction sequences to 4 resulted in the formation of gala-quercitol 14. Quercitols were easily obtained by ammonolysis of acetate derivatives in MeOH. The outcome of dihydroxylation reactions were supported by conformational analysis.
- Salamci,Secen,Sutbeyaz,Balci
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p. 2453 - 2457
(2007/10/03)
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- A novel synthesis of DL-proto-, and DL-vibo- quercitol via 1,4- cyclohexadiene
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Photooxygenation of 1,4-cyclohexadiene 3 followed by reduction with LiAIH4 or thiourea gave (25/1)-cyclohex-3-ene-triol 7a. trans-Hydroxylation of triol 7a with three different methods afforded both of proto-quercitol 1a and vibo-quercitol 2a.
- Salamci, Emine,Secen, Hasan,Suetbeyaz, Yasar,Balci, Metin
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p. 2223 - 2234
(2007/10/03)
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- A Stereocontrolled Synthesis of proto-Quercitol
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Conduritol A tetramethyl ether (2) has been converted by hydroboration-oxidation into proto-quercitol tetramethyl ether (5) which on demethylation afforded a mixture (2:1) of proto-quercitol (4) and vibo-quercitol (11). proto-Quecitol was also obtained (15percent) from conduritol A tetrabenzoate (3) by a similar sequence.
- Cambie, Richard C.,Renner, Noel D.,Rutledge, Peter S.,Woodgate, Paul D.
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p. 1597 - 1602
(2007/10/02)
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- MICROBIAL OXIDATION IN SYNTHESIS: PREPARATION OF MYO-INOSITOL PHOSPHATES AND RELATED CYCLITOL DERIVATIVES FROM BENZENE.
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Pseudomonas putida oxidation of benzene affords cis-3,5-cyclohexadiene-1,2-diol (2) which is used as a novel precursor for the synthesis of D- and L-myo-inositol 1,4,5-triphosphates, (-)-(1) and (+)-(1).The versatility of this approach to functionalised cyclitols is illustrated in the synthesis of myo-inositol 1-phosphate (19), 6-deoxy, 6-deoxy-6-fluoro, and 6-deoxy-6-methyl myo-inositols (31), (37) and (43), and their 1,4,5-trisphosphate derivatives (33), (39) and (45).
- Ley, Steven V.,Parra, Margarita,Redgrave, Alison J.,Sternfeld, Francine
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p. 4994 - 5026
(2007/10/02)
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- Polyfunctionalised Cyclohexanes from Dianhydrodeoxyinositols. cis-Deoxy-1,3(1,4)-inosadiamines from Benzene
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A ca. 9 : 1 mixture (yield 87 - 90percent) of the stereoisomeric (1α,2α,6α)-/(1α,2β,6α)-2-bromo-7-oxa-bicyclohept-3-enes (7a/8a) is obtained via controlled NBS bromination of 4,5-epoxycyclohexene (5). 7a/8a are quantitatively equilibrated in the presence of tetraalkylammonium bromides (the equilibrium being controlled by the polarity of the solvent (3 : 7 in acetonitrile) and are isolated pure by chromatography.Through selective halogen substitution (7b/8b, 9b - d/10b - d) and ammonolysis the allylic epoxy alcohols 9a/10a are obtained in high yields.Stereospecific epoxidation of 7a/8a yields the (1α,2α,3α,5α,7α)-/(1α,2β,3α,5α,7α)-diepoxy bromides 12a/14a.The latter are equilibrated quantitatively to mixtures favoring either one in the ratio of ca. 9 : 1 (CCl4) and 1 : 9 (CH3CN), respectively.Upon SN2 substitution with ammonium acylates (-> 13b, c/15b, c) and ammonolysis the naturally not occurring dianhydrodeoxyinositols 13a/15a are isolated in practically quantitative yields.The usefulness of 13a/15a and of various derivatives for the stereoselective synthesis of cis-1,4- and cis-1,3-disubstituted cyclohexanetriols is exemplified by reactions with monovalent (H2O, HI, NaN3) and divalent nucleophiles (NH2NH2, CH3NHNH2).I.a. the cis-deoxy-1,3-inosadiamines 1 (2-deoxystreptamine)/2 and the cis-deoxy-1,4-inosadiamines 3/4 become available in high yields.
- Kuehlmeyer, Rainer,Keller, Reinhold,Schwesinger, Reinhard,Netscher, Thomas,Fritz, Hans,Prinzbach, Horst
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p. 1765 - 1800
(2007/10/02)
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- THE PREPARATION OF CYCLOHEXANEPENTOLS FROM INOSITOLS BY DEOXYGENATION
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Several cyclohexapenetols heva been synthesized from inositols by blocking all but one hydroxyl group, converting the free hydroxyl group into its S-methyl dithiocarbonate, and treating it with tributylstannane.Suitable blocking-groups are methyl, benzyl, and methylthiomethyl ethers, and acetals.One cyclohexanepentol was prepared by the reductive deamination of an aminodeoxyinositol.
- Angyal, Stephen J.,Odier, Leon
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p. 209 - 220
(2007/10/02)
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