Asymmetric Synthesis of (S,S)- and (R,R)-2-Methylthreitol

Enders, Dieter; Peiffer, Evelyn; Raabe, Gerhard

doi:10.1055/s-2007-965967

Cited by 15 publications

(13 citation statements)

References 6 publications

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“…After acidic methanolysis of the acetonide protection (Dowex 50X2-200) the enantiomeric methylthreitols 82 were obtained in excellent diastereo-and enantiomeric excesses (g98% de, 98% ee) and in good overall yields (40-61% depending on the method used). 134 The SAMP/RAMP-hydrazone methodology was also employed in the enantioselective synthesis of mono-TBSprotected, allylic diols 84 (R 2 ) TBS, ee 90-94%). Alkylation (R 1 ) Bn, i-Pr, n-Bu, (CH 2 ) 2 Ph, 4-t-BuC 6 H 4 CH 2 ) of dioxanone SAMP-hydrazone followed by hydrazone ozonolysis gave the acetonide-protected, R-substituted ketodiols (90-94% ee), which in turn were converted to exocyclic olefins 83 by Wittig reaction without racemization.…”

Section: Alkylation Of Dioxanone Hydrazonesmentioning

confidence: 99%

N,N-Dialkylhydrazones in Organic Synthesis. From Simple N,N-Dimethylhydrazones to Supported Chiral Auxiliaries

2009

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Section: Alkylation Of Dioxanone Hydrazonesmentioning

confidence: 99%

N,N-Dialkylhydrazones in Organic Synthesis. From Simple N,N-Dimethylhydrazones to Supported Chiral Auxiliaries

2009

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“…No X-ray analysis of a (sulfony1imino)-ether is known. As reported by Enders and coworkers [8], the y -1actone hydrazone 21 is a 9 : 1 mixture of the (Z)-and (E)-isomers. The assignment is based upon the 13C-NMR spectrum, where the C(3) signal of the (E)-isomer is shifted upfield by 3.3 ppm, due to a y-effect, and upon the 'H-NMR spectrum, where CH,(3) of the major isomer resonates at higher fields (A6 = 0.17 ppm), similarly to what was observed for hydroximo-lactones [25] [31].…”

mentioning

confidence: 53%

“…According to this mechanism, 4 should react with N,N-dialkylhydrazines to form the desired lactone N, N -dialkylhydrazones. Treatment of lactone tosylimine 4 with a small excess of N,N-dimethylhydrazine (NH,NMe,; 3 h, 25") gave the lactone hydrazone 16 in only 14% [8] yield (Scheme 3 ) . The main product was the crystalline hydrazidine 17 (28 YO).…”

mentioning

confidence: 99%

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ChemInform Abstract: Synthesis of N,N‐Disubstituted Lactone Hydrazones via (Sulfonylimino)‐Ethers.

Fritschi¹,

Vasella²

1992

ChemInform

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The dihydropyran 3 reacts with sulfonyl azides to give the known (sulfony1imino)-ethers ( = lactone sulfonylimines) 4 and 18. Reaction of 4 with NH2NH2. H,O leads to the aminotriazole-dibutanol 5, characterized as its tetraacetate 8, and not, as previously claimed, to 6 or 7. Similarly, the dihydrofuran-derived (tosy1imino)-ether 10 yields 11. The structure of 5 was established by X-ray analysis, and a mechanism for its formation is proposed. Carbanionic derivatives of N,N-dialkylated hydrazones are important intermediates for the regio-, diastereo-, and enantioselective formation of C,C bonds [ 1-41. Carbanionic derivatives of N,N-disubstituted lactone hydrazones of the type 1 and 2 (R',R* = alkyl, Scheme I ) , however, have so far not been used for C,C-bond formations, presumably because they are less easily available and less stable. The only method for the synthesis of N,N-disubstituted lactone hydrazones') is the one of Enders and coworkers [8] who cyclized N,N -dialkyl-o -chlorohydrazides by treatment with AgBF,.We wished to find new methods for the preparation of lactone N,N-dialkylhydrazones derived from valero-and from butyrolactone. These lactone hydrazones may be useful for the preparation of alkylated lactones; they are also models for 2-deoxyglycono-1 3 -and -1,4-lactone hydrazones. We are currently investigating the preparation and use of such glyconolactone hydrazones [9-1 I]. In this context, we noted a report by Huisgen and coworkers [I21 that the dihydropyran 3 reacts with tosyl azide (TsN,) to give the lactone tosylimine 4, and that 4 reacts with hydrazine hydrate (NH,NH,. H,O) in 75 % yield to a crystalline product to which Huisgen and coworkers assigned the structure 6 or 7, based upon an elemental analysis and an IR spectrum. Following their procedure, we obtained 4 and from the latter and NH,NH,. H,O a product (79%) with the same melting point and IR bands as the one reported (Scheme I ) . However, we observed that the reaction mixture developed a pink-to-red colour, and based on the spectral data of the I ) , )Taken from the Diploma Work of S. Fritschi, Zurich, 1989. Lactone imines react with 4-toluenesulfonohydrazides ( = tosylhydrazines) to yield lactone tosylhydrazones [5-71, but the analogous reaction with N,N-dialkylhydrazines did not lead to lactone N,N-dialkylhydrazones PI.

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“…For our study, we needed 2-methylbutane-1,2,3,4-tetraol (tetraol) in gram amounts as racemates and as enantiomerically enriched materials of all of its four stereoisomers. Because of their importance in biological and atmospheric research the syntheses of the stereoisomers of tetraol have been devised already (Cole-Filipiak et al, 2010;Duvold et al, 1997;Ebben et 20 al., 2014;Enders et al, 2007;Fontana et al, 2000;Ghosh et al, 2012;Giner et al, 2002;Hoeffler et al, 2000;Koumbis et al, 2007;Moen et al, 2007;Robinson et al, 2009;Sharma et al, 2008;Urbansky et al, 2004). Among the reported syntheses, the reports of Ghosh et al (Ghosh et al, 2012), Moen et al, (Moen et al, 2007) and Sharma et al (Sharma et al, 2008) appeared most attractive to us as they show an access to both diastereomers through the same reaction sequence and give the four stereoisomers as stereochemically highly homogeneous materials with enantiomeric excesses (ee) of 80-99%.…”

Section: Aqueous Tetraol Samplesmentioning

confidence: 99%

Physical state of 2-methylbutane-1,2,3,4-tetraol in pure and internally mixed aerosols

Lessmeier¹,

Dette²,

Godt³

et al. 2018

Preprint

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Abstract. 2-Methylbutane-1,2,3,4-tetraol (hereafter named tetraol) is an important oxidation product of isoprene and can be considered as a marker compound for isoprene-derived secondary organic aerosols (SOAs). Little is known about this compound's physical phase state, although some field observations indicate that isoprene-derived secondary organic aerosols 10 in the tropics tend to be in a liquid rather than a solid state. To gain more knowledge about the possible phase states of tetraol and of tetraol-containing SOA particles, we synthesized tetraol as racemates as well as enantiomerically enriched materials.Subsequently the obtained highly viscous dry liquids were investigated calorimetrically by differential scanning calorimetry revealing subambient glass transitions temperatures . We also show that only the diastereomeric isomers differ in their values, albeit only by a few kelvin. We derive the phase diagram of water/tetraol mixtures over the whole tropospheric 15 temperature and humidity range from determining glass transition temperatures and ice melting temperatures of aqueous tetraol mixtures. We also investigated how water diffuses into a sample of dry tetraol. We show that upon water uptake two homogeneous liquid domains form that are separated by a sharp, locally constrained concentration gradient. Finally, we measured the glass transition temperatures of mixtures of tetraol and an important oxidation product of α-pinene-derived SOA:3-methylbutane-1,2,3-tricaboxylic acid (3-MBTCA). Overall, our results imply a liquid-like state of isoprene-derived SOA 20 particle in the lower troposphere at moderate to high relative humidity, but presumably a semisolid or even glassy state at upper tropospheric conditions, particularly at low relative humidity, thus providing experimental support for recent modelling calculations. 30Atmos. Chem. Phys. Discuss., https://doi

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Asymmetric Synthesis of (S,S)- and (R,R)-2-Methylthreitol

Cited by 15 publications

References 6 publications

N,N-Dialkylhydrazones in Organic Synthesis. From Simple N,N-Dimethylhydrazones to Supported Chiral Auxiliaries

N,N-Dialkylhydrazones in Organic Synthesis. From Simple N,N-Dimethylhydrazones to Supported Chiral Auxiliaries

ChemInform Abstract: Synthesis of N,N‐Disubstituted Lactone Hydrazones via (Sulfonylimino)‐Ethers.

Physical state of 2-methylbutane-1,2,3,4-tetraol in pure and internally mixed aerosols

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