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A tinglucal tributyl[4,6-O-bis(t-butyl)silylidene-3-O-tris(isopropyl)silyl]tin 7 and a triflate derived from isolevoglucosenone (1R,4R,5R)-4-benzyloxy-6,8-dioxabicyclo[3.2.1]oct-2-en-2-yl trifluoromethanesulfonate 10 undergo the carbonylative Stille conden ...
The syntheses of new C8-carbasugars and -aminocyclitols related to miglitol and voglibose are described. The key step involves the ring closing metathesis of 1,9-dienes derived from D-mannitol. Chemical transformations of the newly created double bond of t ...
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 ...
2-Methylprop-2-ene-1-sulfonyl fluorides can be easily prepared via the ene reaction of methallylsilanes and SO2. In the presence of a base, aldehydes and 2-methylprop-2-ene-1-sulfonyl fluorides give 1.3-(E) and (Z)-dienes. Their (Z) --> (E) isomerization b ...
Condensation of a silylated beta-D-galactopyranosylaldehyde (3) with isolevoglucosenone (4) in the presence of Et(2)AII provided bicyclic enone 5. Subsequent addition of BnNHOMe gave adduct 6, which was converted into 4-O-acetyl-1,6-anhydro-3-C-[ R)1.3,4,5 ...
Eight new seven-membered ring iminoalditols, displaying an amino group and a hydroxymethyl group on the ring, have been synthesized from D-arabinose via epoxidation of a protected azacycloheptene and subsequent nucleophilic opening. Three of them show a po ...
An efficient and concise total synthesis of (+)-lentiginosine (1) starting from an L-tartaric acid-derived nitrone using organometallic addition, indium-catalyzed reduction, and ring-closing metathesis reaction as the key steps is reported. Structural anal ...
In the presence of a Lewis or protic acid and at low temperature, 1,3-dioxy-1,3-dienes add to sulfur dioxide generating zwitterionic intermediates that can react with carbon nucleophiles such as allylsilanes. After a retro-ene elimination of SO2, valuable ...
The 'naked sugars' (+)- and (-)-7-oxabicyclo[2.2.1]hept-5-en-2-one have been converted into (-)-conduramine B-1 ((-)3) and its enantiomer (+)-3, respectively. They have been condensed with a variety of aldehydes in the presence of NaBH(OAC)(3). The N-subst ...
At low temperature, 1-alkoxy-1,3-dienes add to sulfur dioxide activated by a Lewis or protic acid generating zwitterionic intermediates that can be quenched by enoxysilanes. The resulting beta,gamma-unsaturated silyl sulfinates can be desilylated by 1:1 Pd ...
