93339-60-7Relevant articles and documents
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.
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.
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.
