Alkenyl Carbonyl Derivatives in Enantioselective Redox Relay Heck Reactions: Accessing α,β-Unsaturated Systems
摘要:
A highly enantioselective and site-selective Pd-catalyzed arylation of alkenes linked to carbonyl derivatives to yield alpha,beta-unsaturated systems is reported. The high site selectivity is attributed to both a solvent effect and the polarized nature of the carbonyl group, both of which have been analyzed through multidimensional analysis tools. The reaction can be performed in an iterative fashion allowing for a diastereoselective installation of two aryl groups along an alkyl chain.
A gas chromatographic investigation of the volatile part of a pineapple concentrate led to the identification of 59 substances, 35 of which were not previously found in pineapple. The identifications and syntheses of some esters (Δ3- and Δ4-unsaturated, β-hydroxy, β-acetoxy, and δ-acetoxy) and of a new sulfur compound are given.
Composition of the Cloacal Gland Secretion of Tuatara,<i>Sphenodon punctatus</i>
作者:Birte Flachsbarth、Matthias Fritzsche、Paul J. Weldon、Stefan Schulz
DOI:10.1002/cbdv.200800265
日期:2009.1
secretions revealed triacylglycerols as major glandular constituents. Twelve major medium-chain fatty acids were found to be conjugated to glycerol in different combinations, resulting in complex mixtures. These acids were identified by transesterification and subsequent derivatization of natural samples, and their structures were verified by synthesis. The natural glycerides contain predominantly three of
Construction of Chemical Libraries of Volatile Compounds by Combinatorial Synthesis of Homologous Mixtures: Alk‐4‐en‐1‐ols, Alk‐4‐enals and Methyl Alk‐4‐enoates
作者:Coline Perrin、Nicolas Baldovini
DOI:10.1002/cbdv.202200817
日期:2023.2
for their identification in GC/MS analyses. We demonstrate here that compound libraries can be prepared by combinatorial syntheses using long linear synthetic sequences, i. e., eight step in the case of 4-enals. The resulting mixtures of homologues are still perfectly exploitable to deliver the requested information such as clean mass spectra and good gaschromatographicretentionindices.
包含 66 个线性化合物的化合物库,六个分子家族的 11 个代表:( E )- 和 ( Z )-alk-4-en-1-ols、alk-4-enals 和甲基 alk-4-enoates 的异构体, 是通过组合合成制备的, 以允许创建直接可用于在 GC/MS 分析中识别它们的质谱数据库。我们在这里证明化合物库可以通过使用长线性合成序列的组合合成来制备,即。即,在 4-enals 的情况下为八步。由此产生的同系物混合物仍然可以完美地用于提供所需的信息,例如干净的质谱和良好的气相色谱保留指数。
Defense mechanisms of arthropods. 83. .alpha.- and .beta.-Necrodol, novel terpenes from a carrion beetle (Necrodes surinamensis, Silphidae, Coleoptera)