Asymmetric syntheses of new polyhydroxylated quinolizidines: Cross-aldol reactions of 7-oxabicyclo[2.2.1]heptan-2-one and 3a,4a,7a,7b-tetrahydro[1,3]dioxolo[4,5]furo[2,3-d]isoxazole-3-carbaldehy de derivatives
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Sulphur dioxide reacts with 1-oxydienes generating zwitterions which are quenched by enoxysilanes to form substituted silyl alkenylsulfinates. These intermediates are desilylated with Bu4NF and the resulting sulfinates react with MeI giving the correspondi ...
The stereoselective synthesis of new 3,4-dihydroxypyrrolidine derivatives starting from D-mannose, D-ribose and L-fucose is presented. Two synthetic strategies employing organometallic addition to hemiacetalic sugars followed by selective nucleophilic disp ...
A diastereoselective three-component synthesis of chiral 2-(1,2-diaminoalkyl)phenols from an electron-rich phenol, an amine, and a chiral alpha -N,N-dibenzylamino aldehyde is developed. The diastereoselectivity of this phenolic Mannich reaction is temp.-de ...
This article describes BP86/SV(P) (DFT) calcns. on a representative set of weakly coordinating anions (WCAs) of type [M(L)n]-, their parent neutral Lewis acids M(L)n-1 and their ate complexes with fluoride, i.e., [FM(L)n]n-1 (M = B, L = F, OTeF5, C6H5, C6F ...
New pyrrolidine-3,4-diol derivatives were prepared from D-(-)- and L(+)-phenylglycinol and tested for their ability to inhibit 25 commercial glycosidases. The influence of the substitution of the lateral side chain and of the pyrrolidine ring on the enzyme ...
The first aza-C-disaccharide (D-azaMan-beta-CHz-(1 -> 6)-D-Man-alpha-OMe) that mimicks alpha-D-Manp-(1 -> 6)-alpha-D-ManOMe was made in 1994 by Johnson and coworkers. Several synthetic approaches to these disaccharide mimetics have been proposed. These are ...
Hot alkyne! The in situ generation of Ethynyl-1,2-BenziodoXol-3(1H)-one (EBX) from the corresponding silyl protected reagent using TBAF is reported. EBX displayed exceptional acetylene transfer ability to stabilized enolates, even at –78 °C. The mild react ...
Enzymes that are involved in the synthesis and processing of oligosaccharides, such as glycosidases, are important catalysts for the specific assembly of oligosaccharide structures on proteins. Design and preparation of selective inhibitors of these enzyme ...
New 2-(aminomethyl)-5-(hydroxymethyl)pyrrolidine-3,4-diol derivatives were synthesized from (5S)-5-[(trityloxy)methyl]pyrrolidin-2-one (6) (Schemes 1 and 2) and their inhibitory activities toward 25 glycosidases assayed (Table). The influence of the config ...
N-Benzyloxycarbonyl-2,5-dideoxy-2,5-imino-3,4-O-isopropylidene-L-ribose 12a has been converted into (1R,2S,6R, 7S,7aS)-5 and (1R, 2S, 6S, 7R, 7aR)-1,2,6,7-tetrahydroxypyrrolidin-5-ones 6 and (1R,2S,6S,7S,7aS)-7 and (1R,2S,6R,7R,7aS)-1,2,6,7-tetrahydroxypyr ...
