A convergent total synthesis of leustroducsin B (1), which is known to exhibit a variety of biological activities, was successfully carried out. Notable features of our synthesis include construction of the C8 stereocenter by lipase-mediated desymmetrization of meso-diol 4 (90.2% ee) and preparation of the C9-C11 anti-diol moiety by the addition of alkynylzinc reagent 20 to the aldehyde 19. Furthermore, a new diol protecting group, p-silyloxybenzylidene, was developed for the deprotection from densely functionalized substrates under weakly acidic conditions. The protecting group was easily removed in a two-step procedure ((HF)3.Et3N; AcOH-THF-H2O).
A convergent total synthesis of leustroducsin B (1), which is known to exhibit a variety of biological activities, was successfully carried out. Notable features of our synthesis include construction of the C8 stereocenter by lipase-mediated desymmetrization of meso-diol 4 (90.2% ee) and preparation of the C9-C11 anti-diol moiety by the addition of alkynylzinc reagent 20 to the aldehyde 19. Furthermore, a new diol protecting group, p-silyloxybenzylidene, was developed for the deprotection from densely functionalized substrates under weakly acidic conditions. The protecting group was easily removed in a two-step procedure ((HF)3.Et3N; AcOH-THF-H2O).
A Further Synthesis of an Analogue of the Antifungal/Antiherbivore Lipid from Avocado
作者:Raymond M. Carman、Tomislav Karoli
DOI:10.1071/c98063
日期:——
A further synthesis of the saturated racemic derivative (1b) of the avocado
diene (1a)
((R,Z,Z)-2-hydroxy-4-oxohenicosa-12,15-dien-1-yl
acetate; "persin") is described.
Diastereoselectivity in the directed aldol reactions of 1-fluoro-3,3-dimethyl-butanone enolates and enol silyl ethers.
作者:John T. Welch、Karl W. Seper
DOI:10.1016/s0040-4039(01)81575-6
日期:——
High diastereoselectivity was observed in the directed aldol reaction of lithium enolates of 1-fluoro-3,3-dimethylbutanone while an apparent reversal of diastereoselection was found in Lewis acid mediated reactions of corresponding enol silyl ethers.
The present invention relates to a process for preparing Nebivolol and, more particularly, to an improved process for synthesizing enantiomerically enriched 6-fluoro chroman alcohol or epoxide derivatives of formula, wherein R and X is defined in the description; as useful intermediates in the preparation of Nebivolol.
Method for producing hydrocarbons and oxygen-containing compounds from biomass
申请人:Golubkov Igor
公开号:US20050112739A1
公开(公告)日:2005-05-26
The present invention generally relates to biochemical and chemical industry, and more particularly to a method which can be used in fermenting carbohydrate substrates of plant origin for producing C
1
-C
5
alcohols, and for synthesis of higher alcohols, other oxygen-containing compounds and hydrocarbons as well as for the production of motor fuel components from biomass. Since C
6
and higher alcohols, ethers, acetals, and higher hydrocarbons are not obtainable by a direct biochemical route, it is proposed to synthesize these using known chemical reactions, wherein by-products of fermentation are as raw materials for said synthesis.
本发明一般涉及生物化学和化学工业,尤其涉及一种可用于发酵植物源碳水化合物底物以生产 C
1
-C
5
醇、合成高级醇、其他含氧化合物和碳氢化合物以及从生物质中生产汽车燃料成分的方法。由于 C
6
和更高的醇类、醚类、乙缩醛和更高的碳氢化合物无法通过直接的生化途径获得,因此建议使用已知的化学反应合成这些物质,其中发酵的副产品可作为上述合成的原料。
METHOD FOR PRODUCING HYDROCARBONS AND OXYGEN-CONTAINING COMPOUNDS, FROM BIOMASS