Fleming−Tamao Oxidation and Masked Hydroxyl Functionality: Total Synthesis of (+)-Pramanicin and Structural Elucidation of the Antifungal Natural Product (−)-Pramanicin
摘要:
The total synthesis of (+)-pramanicin (41b) is reported, thereby establishing the relative and absolute stereochemistry of the naturally occurring antifungal agent. The key steps involve (i) conjugate addition of the diethyl((diethylamino)diphenylsilyl)zincate to a suitably protected gamma-lactam 3 and quenching of the resultant enolate with the alpha,beta-unsaturated gamma,delta-epoxy aldehyde 2 (X = H), (ii) Ni(acac)(2)-catalyzed hydroxylation of a beta-dicarbonyl array, and (iii) Fleming-Tamao oxidation to reveal the masked C-3 hydroxyl group.
Fleming−Tamao Oxidation and Masked Hydroxyl Functionality: Total Synthesis of (+)-Pramanicin and Structural Elucidation of the Antifungal Natural Product (−)-Pramanicin
摘要:
The total synthesis of (+)-pramanicin (41b) is reported, thereby establishing the relative and absolute stereochemistry of the naturally occurring antifungal agent. The key steps involve (i) conjugate addition of the diethyl((diethylamino)diphenylsilyl)zincate to a suitably protected gamma-lactam 3 and quenching of the resultant enolate with the alpha,beta-unsaturated gamma,delta-epoxy aldehyde 2 (X = H), (ii) Ni(acac)(2)-catalyzed hydroxylation of a beta-dicarbonyl array, and (iii) Fleming-Tamao oxidation to reveal the masked C-3 hydroxyl group.
We report herein a regio‐ and stereoselective photocatalytic hydrogenolysis of allylicalcohols to form unsaturated hydrocarbons employing a palladium(II)‐loaded titanium oxide; the reaction proceeds at room temperature under light irradiation without stoichiometric generation of salt wastes. Olefin and saturated alcohol moieties tolerated the reaction conditions. Hydrogen atoms were selectively incorporated
Alkyltitanium alkoxides generally serve as nucleophiles in reactions with carbonyl compounds and cross-coupling. Their application as reductants is known but remains underdeveloped. Here, we report that irradiation with visible light makes these organometallic compounds efficient reducing agents for the dehalogenation of 1,2- and 1,3-haloalcohols. This reaction was utilized for the reduction of epoxides
THERMOPLASTIC RESIN FILM WITH SATISFACTORY PRINTABILITY
申请人:Yupo Corporation
公开号:EP1172400A1
公开(公告)日:2002-01-16
Described is a thermoplastic resin film having on a surface thereof a hydroxy-modified imine polymer containing repeating units represented by the following general formula (I) in an amount of 5 mol% or more based on the total of repeating units. This thermoplastic resin film has ink transfer, adhesion and aging stability, and excellent printability of generating no back ghost when offset printing using oxidation polymerization type ink is performed on both faces.
Thermoplastic resin film satisfactory in printability
申请人:YUPO CORPORATION
公开号:US20020054991A1
公开(公告)日:2002-05-09
Described is a thermoplastic resin film having on a surface thereof a hydroxy-modified imine polymer containing repeating units represented by the following general formula (I) in an amount of 5 mol % or more based on the total of repeating units. This thermoplastic resin film has ink transfer, adhesion and aging stability, and excellent printability of generating no back ghost when offset printing using oxidation polymerization type ink is performed on both faces
1
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