- Synthesis and utilisation of chiral 3-hydroxy perhydropyrrolo [2,1-c] [1,4] oxazin-4-one as a novel precursor for the enantioselective synthesis of α-hydroxy carboxylic acids
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A novel strategy for the enantioselective synthesis of several α- hydroxy carboxylic acids by the nucleophilic alkylation of chiral 3-hydroxy- (3S, 8aS)-perhydropyrrolo [2,1-C] [1,4] oxazin -4 one is reported.
- Pandey, Ganesh,Das, Parthasarathi,Reddy, Paidi Y.
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- Facile synthesis of α-hydroxy amides and esters by direct autoxidation of their titanium enolates
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The autoxidation of titanium enolates 2, derived from amides and esters 1, afforded either directly the corresponding α-hydroxy carbonyl compounds 3 or, by variation of the reaction conditions, the γ-hydroxy β-keto ester 4 from ester 1g in good yields (64
- Adam,Metz,Prechtl,Renz
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- Photoinduced electron transfer (PET) promoted oxidative activation of 1- (N-benzyl-N-methylglycyl)-(S)-prolinol: Development of novel strategies towards enantioselective syntheses of α-amino acids, their N-methyl derivatives and α-hydroxy acids employing
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PET activation of 1-(N-benzyl-N-methylglycyl)-(S)-prolinol (1) in dry acetonitrile, utilizing 1,4-dicyanonaphthalene (DCN) as a light-harvesting electron-acceptor and methyl viologen (MV++) as an electron-transfer mediator, leads to the formati
- Pandey, Ganash,Das, Parthasarathi,Reddy, P. Yella
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p. 657 - 664
(2007/10/03)
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- Asymmetric reactions of α-ketoacid-derived hemiacetals: Stereoselective synthesis of α-hydroxy acids
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N-Acylation of prolinol with α-ketoacid chlorides results in concomitant hemiacetalization of the α-keto amide by the prolinol hydroxyl group. (R) or (S) α-hydroxy acids are obtained with good enantiomeric excess by stereodivergent reduction of these hemiacetals. Reaction with Grignard reagents at ambient temperature furnishes (R) α-alkyl mandelic acids with good stereoselectivity.
- Pansare, Sunil V.,Ravi, R. Gnana
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p. 14549 - 14564
(2007/10/03)
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- Electrochemically induced oxidative rearrangement of alkylidenemalonates
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Alkylidenemalonates capable of double bond migration being electrolyzed in methanol or ethanol in the presence of alkali metal halides in an undivided cell equipped with Fe cathode are transformed into 2-alkyl-3,3- dimethoxyalkane-1,2-dicarboxylates in 70-90% yield via electrochemically induced oxidative rearrangement. Acidification of the reaction mixture after the electrolysis leads to the formation of 2-alkyl-3-oxoalkane-1,1- dicarboxylates. In the case of isobutylidenemalonate, the electrolysis intermediate dimethyl 3,3-dimethyl-2-methoxy-cyclopropane-1,1-dicarboxylate was isolated in 70% yield.
- Elinson, Michail N.,Feducovich, Sergey K.,Nikishin, Gennady I.
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p. 14529 - 14540
(2007/10/03)
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- Stereodivergent Approach to α-Hydroxy Acids Involving Substrate Directed Reduction of α-Keto Amides
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Substrate directed reduction of 'S'-2-hydroxymethylpyrrolidine derived α-keto amides with tetramethylammonium triacetoxyborohydride proceeds with good stereoselectivity at room temperature.A reversal of stereoselectivity is observed in reductions with conventional borohydride reducing agents in protic solvents.
- Pansare, Sunil V.,Ravi, R. Gnana
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p. 5959 - 5962
(2007/10/02)
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- ASYMMETRIC SYNTHESIS OF α-HYDROXY CARBOXYLIC ACIDS: DIRECT OXIDATION OF CHIRAL AMIDE ENOLATES USING 2-SULFONYLOXAZIRIDINES
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The direct oxidation of chiral amide enolates to optically active mandelic acid using 2-sulfonyloxaziridine 1 is described.The diastereoselectivity is counterion dependent.
- Davis, Franklin A.,Vishwakarma, Lal C.
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p. 3539 - 3542
(2007/10/02)
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