93339-60-7Relevant academic research and scientific papers
Deracemization of 1,2-diol monotosylate derivatives by a combination of enzymatic hydrolysis with the Mitsunobu inversion using polymer-bound triphenylphosphine
Shimada, Yasutaka,Usuda, Kazumasa,Okabe, Hirokazu,Suzuki, Tsuguru,Matsumoto, Kazutsugu
experimental part, p. 2802 - 2808 (2010/03/30)
The deracemization of 1,2-diol monotosylate derivatives is achieved by the sequential combination of enzymatic hydrolysis and Mitsunobu inversion using a polymer-bound triphenylphosphine. After the lipase-catalysed hydrolysis of the racemic 2-acetoxyhexyl tosylate, the subsequent Mitsunobu reaction without separation causes an inversion of the resulting (R)-alcohol to give the (S)-enantiomer of the acetate as a single product. In particular, the reaction using the polymer-bound triphenylphosphine also proceeds smoothly, and the product is easily separated by filtration from the polymer-bound reagent and its by-products. This deracemization process is applicable to the preparation of several optically active 1,2-diol monotosylates.
Preparation of optically active 1,2-diol monotosylates by enzymatic hydrolysis
Shimada, Yasutaka,Sato, Hiroshi,Minowa, Shinji,Matsumoto, Kazutsugu
, p. 367 - 370 (2008/04/01)
An easy preparation of optically active 1,2-diol monotosylate derivatives by enzymatic hydrolysis is disclosed. Lipase PS (Burkholderia cepacia) catalyzes the hydrolysis of racemic 2-acetoxyhexyl tosylate with excellent enantioselectivity to afford the corresponding optically active compounds. In this reaction, a unique temperature effect is observed. After optimizing the reaction conditions, this procedure is widely applicable to the practical preparation of both enantiomers of various optically active compounds with high ee. Georg Thieme Verlag Stuttgart.
Titanocene-catalyzed reductive epoxide opening: The quest for novel hydrogen atom donors
Gansaeuer, Andreas,Barchuk, Andriy,Fielenbach, Doris
, p. 2567 - 2573 (2007/10/03)
Novel hydrogen atom donors for the reductive titanocene-catalyzed epoxide opening are presented. While the potentially attractive cyclopentadienes gave only moderate yields of the desired alcohols, substituted, nontoxic, and commercially available 1,4-cyclohexadienes, e.g. γ-terpinene, in combination with more elaborate catalysts gave better or similar results than the much more expensive and carcinogenic 1,4-cyclohexadiene. In the practically important reactions of Sharpless epoxides and their derivatives excellent levels of regioselectivity for the epoxide opening could be obtained. The toxic and unpleasant to handle tert-butyl thiol could be replaced while increasing the yields of the desired products.
C-1 Reactivity of 2,3-Epoxy Alcohols via Oxirane Opening with Metal Halides: Application and Synthesis of Naturally Occuring 2,3-Octanediol, Muricatacin, 3-Octanol, and 4-Dodecanolide
Bonini, Carlo,Federici, Chiara,Rossi, Leucio,Righi, Giuliana
, p. 4803 - 4812 (2007/10/02)
The C-1 reactivity of 2,3-epoxy alcohols and derivatives has been examined thoroughly.In the first approach a rearrangement opening of 2,3-epoxy alcohols with LiI leads to 1-iodo 2,3-diols with erythro or threo stereochemistry starting from trans or cis epoxy alcohols.Subsequent coupling with a carbon nucleophile can lead to a series of vicinal diols with predicted relative and absolute stereochemistry: the described methodology has been applied to the asymmetric synthesis of the naturally occuring (S,S)-2,3-octanediol and (R,R)-muricatacin.The second approach, starting from easily available tosyloxy epoxides, leads to the highly regioselective opening of the oxirane ring with Li halides.The 3-iodohydrins obtained can be reduced to the corresponding 1-(tosyloxy)alkan-2-ols and then coupled with common carbon nucleophiles to afford, in high yields, optically active alcohols.This methodology has been applied to the asymmetric synthesis of naturally occuring pheromones like 3(R)-octanol and 4(R)-dodecanolide.
A Systematic Study on the Bakers'Yeast Reduction of 2-Oxoalkyl Benzoates and 1-Chloro-2-alkanones
Sakai, Takashi,Wada, Kou,Murakami, Takahiko,Kohra, Kiichiro,Imajo, Norihisa,et al.
, p. 631 - 638 (2007/10/02)
The bakers' yeast reduction of a series of 2-oxoalkyl arenecarboxylates (1a-f) (R=CH3 to n-C6H13; X=H) and the phenyl-modified derivatives (1g-l) (R=n-C5H11, X=OH, CH3, F, Cl, Br, or I) as well as 1-chloro-2-alkanones R(C=O)CH2Cl (6a-f) (R=CH3 to n-C6H13) were systematically investigated.The substrate specificities, configuration and percentee of the reduction products were found to be highly dependent on the length of the alkyl group (R) and the α substituent.Thus, the benzoates 1a-f gave optically active 2-hydroxyalkyl benzoates (2a-f) (R, configuration, percentee) (a: CH3, S, 99; b: C2H5, S, 98; c: C3H7, S, 26; d: n-C4H9, R, 55; e: n-C5H11, S, 15; f: n-C6H13, S, 63) in 11-91percent yields.Among the modification experiments of the phenyl group, 1g-l, the p-iodo substituent markedly increased the ee from 15 to 71percent, although the yield was rather lowered (22percent yield).The reduction of α-chloro ketones 6a-f also gave optically active 1-chloro-2-alkanols (7a-f) in 16-69percent yields.
A CHEMOENZYMATIC ACCESS TO OPTICALLY ACTIVE 1,2-EPOXIDES
Chen, Ching-Shih,Liu, Yeuk-Chuen
, p. 7165 - 7168 (2007/10/02)
Lipase-catalyzed transacylation in organic media was employed to produce optically active α-hydroxy tosylate which could be readily converted to the corresponding 1,2-epoxides with high optical purity.
