19461-34-8Relevant articles and documents
Lipase-mediated kinetic separation of a diastereomeric mixture of 4-tert-butylcyclohexanemethanol
Hiroya,Hasegawa,Watanabe,Ogasawara
, p. 379 - 381 (2007/10/02)
Diastereomerically pure trans- and cis-4-tert-butylcyclohexanemethanols have been obtained by kinetic acylation of the diastereomeric alcohol in an organic medium and by kinetic deacylation of the diastereomeric acetate in an aqueous medium both in the presence of the same lipase (lipase PS, Pseudomonas sp., Amano). The reactions take place preferentially with the trans-isomers both in organic and aqueous media to give the trans-acetate with recovery of the cis-alcohol on acylation in an organic medium,and the trans-alcohol with recovery of the cis-acetate on deacylation in an aqueous medium.
Deoxy-nitrosugars. Stereoelectronic Control in the Reductive Denitration of Tertiary Nitro Ethers. A Synthesis of 'C-Glycosides'
Baumberger, Franz,Vasella, Andrea
, p. 2210 - 2222 (2007/10/02)
The separate, radical denitration with Bu3SnH of the pyranose derivatives 3, 4, 9, and 10 gave in good yields exclusively the 'C-glycosides' 5 and 11, respectively (Scheme 1).Similar reduction of the cylohexyl derivatives 15, 16, 19 and 20 gave 4:1 mixtures of 17, 18, 21 and 22, respectively, always with predominant formation of an axial C,H-bond.In the furanose series a divergent behaviour was observed for the D-mannose-derived nitro ethers 25 and 27 and the D-ribose-derived nitro ethers 30 and 31, respectively, in that the former two gave isomerically homogeneous reduction products (26 and 28, respectively; Scheme 3) and the latter a 1:1 mixture of the diastereoisomers 32 and 33 (Scheme 4).The stereochemical results were explained on the basis of the stereoelectronic effect of the ring O-atom, the preferred conformation of the intermediate, pyramidal alkoxyalkyl radicals and steric effects in the trioxabicyclooctane ring system.
