24347-57-7

Upstream product

• 10229-10-4 pent-3-yn-1-ol 
• 52813-63-5 (5R)-2,3,4,5-tetrahydro-5-hydroxymethyl-2-furanone 
• 29264-40-2 5-pentenylbenzoate 
• 144762-81-2 C₂₁H₃₈N₂O₆ 
• 58879-34-8 (S)-5-tosyloxypentan-4-olide 
• 625-31-0 (S)-4-penten-2-ol 
• 112789-84-1 (+)-(S)-ethyl 4-hydroxypentanoate 
• 52813-64-6 (R)-5-(chloromethyl)tetrahydro-2-furanone 
• 58879-33-7 (R)-(-)-γ-<(tosyloxy)methyl>-γ-butyrolactone 

Downstream Products

• 93929-68-1 (1R,2S,4S)-2-<(6S)-t-butyldimethylsilyloxy-1-heptynyl>-4-(2-methoxyethoxymethoxy)-1-cyclopentylmethyl benzyl ether 
• 20350-15-6 (+)-brefeldin A 
• 74500-57-5 (S)-4-t-butyldimethylsilyloxy-1-trityloxypentane 
• 155853-18-2 {(S)-6-[(1R,2R,4S)-2-[(S)-2-Benzyloxy-1-(2-methoxy-ethoxymethoxy)-ethyl]-4-(2-methoxy-ethoxymethoxy)-cyclopentyl]-1-methyl-hex-5-ynyloxy}-tert-butyl-dimethyl-silane 
• 74500-59-7 (4S)-4-[tert-butyl(dimethyl)silyl]oxypentyl 4-methylbenzenesulfonate 
• 74500-56-4 (S)-5-Trityloxy-pentan-2-ol 
• 19041-15-7 (S)-γ-valerolactone 

Relevant academic research and scientific papers

Chiral α,ω-Dioxy-Carbanions from 1,3-Propanediol and 1,4-Butanediol by Sparteine-Assisted Deprotonation. Enantioselective Synthesis of 1,3- and 1,4-Diols, (R)-Pantolactone, and a Cyclopropane

Prostereogenic mono- and dicarbamates of 1,3-propanediol and 1,4-butanediol are deprotonated by the sec-butyllithium/(-)-sparteine system with high enantiotopic differentiation.The electrophilic substitution of the intermediate chiral carbanions furnishes the title compounds with >95percent ee. Key words: Chiral 1-oxy-carbanions; enantioselective deprotonation; (-)-sparteine.

Combination of Metal-Catalyzed Cycloisomerizations and Biocatalysis in Aqueous Media: Asymmetric Construction of Chiral Alcohols, Lactones, and γ-Hydroxy-Carbonyl Compounds

The combination of the metal-catalyzed cycloisomerization of alkynes containing a tethered nucleophile as substituent in aqueous media (followed by the spontaneous hydrolysis, hydroalkoxylation, or aminolysis of the transiently formed five-membered heterocycles) with the subsequent enantioselective ketone bioreduction (mediated by KREDs) has been achieved. The overall transformations, which formally involve a three-step one-pot reaction, provide a variety of enantiopure valuable molecules (e.g., 1,4-diols, lactones, and γ-hydroxy-carbonyl compounds (carboxylic acids, esters, and amides)) with high conversions and enantioselectivities and under mild reaction conditions, disclosing the concept of integrated metal-catalyzed cycloisomerizations of alkynes and enzymatic catalysis in water.

From Stereodefined Cyclobutenes to Dienes: Total Syntheses of Ieodomycin D and the Southern Fragment of Macrolactin A

A copper-promoted flexible synthesis of cyclobutenes carrying simple alkyl chains, enabling even the most hindered nucleophiles to be employed, has been developed. The versatility of this approach was exemplified by a short total synthesis of ieodomycin D and a straightforward preparation of the southeastern fragment of macrolactin A. The latter features a late-stage, double cyclobutene electrocyclic ring opening that directly delivers a bis-diene of defined geometry.

Asymmetric synthesis of 2-substituted butane-1,4-diols by hydrogenation of homochiral fumaramide derivatives

Diastereoselective hydrogenation of homochiral fumaramides 1 derived from (2R)-Oppolzer's sultam was observed by analysis of the 1H NMR spectra of the succinamide mixtures with de's of 77-88%. Reduction of these succinamides using LiAlH4 gave the corresponding (2S)-butane-1,4- diols and established that addition of hydrogen takes place selectively on the re-face of fumaramides 1. The stereoselectivity was confirmed by estimating the ee's from the 19F NMR spectra of the Mosher's diesters of the diols. This methodology was applied to the synthesis of selected pyrrolidine natural products in homochiral form.

Asymmetric Hydrosilylation of 1-Alkenes Catalyzed by Palladium-MOP

Asymmetric hydrosilylation of simple terminal alkenes (RCH=CH2) with trichlorosilane at 40 deg C in the presence of 1*10-3 or 1*10-4 molar amounts of palladium catalyst prepared in situ from 3-C3H5)>2 and (S)-2-diphenylphosphino-2'-methoxy-1,1'-binaphthyl ((S)-MeO-MOP) proceeded with unusual regioselectivity and with high enantioselectivity to give high yields of 2-(trichlorosilyl)alkanes together with a minor amount of 1-(trichlorosilyl)alkanes.Optically active alcohols, RCH(OH)CH3, were obtained by oxidation of the carbon-silicon bond.Regioselectivities for forming 2-silylalkanes over 1-silylalkanes and enantiomeric purities of alcohols are as follows: R=n-C4H9: 89/11, 94percent ee (R).R=n-C6H13: 93/7, 95percent ee (R).R=n-C10H21: 94/6, 95percentee (R).R=PhCH2CH2: 81/19, 97percentee (S).R=PhCH2CH2CH2: 80/20, 92percent ee (R).R=cyclo-C6H11: 66/34, 96percent ee (R).A similar hydrosilylation of 1-alkenes, 4-pentenyl benzoate and 1,5-heptadiene gave corresponding 2-alkanols of 90percent ee and 87percent ee, respectively, the ester carbonyl and the internal double bond remaining intact.

Substrate structure and incubation-parameter-dependent selectivities in chiral discrimination of galactopyranosides by β-galactosidase hydrolysis

Mono-β-galactopyranosides of (+/-)-propane-1,2-diol, (+/-)-butane-1,3-diol, (+/-)-pentane-1,4-diol, (+/-)-butan-2-ol, (+/-)-pentan-2-ol and (+/-)-1,2-O-isopropylideneglycerol were synthesized by the Koenigs-Knorr reaction using hydroxycarbonyl compounds as precursors for the diolic substrates.Hydrolysis of 3-hydroxybutyl β-D-galactopyranoside 18 by β-galactosidases from Eschrichia coli, Aspergillus oryzae, Kluyveromyces lactis and Bacillus circulans, respectively, resulted in each case in an enantiomeric enrichment of the released diol.This was most significant with the E. coli enzyme and and increased with higher reaction temperature and shorter incubation periods.Under standartized conditions, cleavage of all synthesized galactopyranosides by this enzyme showed the highest stereoselectivity for butane-1,3-diol, butan-2-ol and isopropylideneglycerol with enantiomeric excesses in the range 60-75percent.For compounds with structural similarity to the natural substrate lactose, enhanced stereodiscriminations were expected.However, this could not be confirmed and instead a specific hydrophobic interaction is suggested to play a crucial role.

Stereocontrolled Synthesis of Dihydroxycyclopentane Derivative: Enantioselective Synthesis of (+)-Brefeldin A

A novel enantioselective synthesis of (+)-brefeldin A was achieved via stereocontrolled one-pot synthesis of a dihydroxycyclopentane derivative from allyl phenyl sulfone and chiral diepoxide.

Bakers' Yeast Reductions of Alkyl Levulinates: Synthesis of (R)-(+) and (S)-(-) 4-Methylbutyrolactones

The bakers' yeast reduction of a number of alkyl levulinates occurs in good to moderate yields to give the corresponding (S) alcohols in >98percent ee.The (S) alcohol 1a has been converted to synthetically useful (S)- or (R)-4-methylbutyro-lactone and (S)-(+)-1,4-pentanediol in good yields.

Cyclodehydration of Non-aromatic Diols on Al(III)-Montmorillonite Clay: Reactivity and Mechanism

Al(III)-Montmorillonite-catalysed reactions of non-aromatic diols and butane-1,4-dithiol into the corresponding heterocyclic compounds are described.Experiments with S-(+)-pentane-1,4-diol indicate a mechanism involving competitive protonation of the primary and secondary hydroxy groups, followed by SN2 displacement of water to form the cyclic product.A comparison of the relative catalytic efficiencies of Al(III)-montmorillonite and the corresponding alumina pillared clay suggests that the performance of the former is superior in the above acid-catalysed reactions.