作者:Ruben Leenders、Marc van de Sande、Jean-François Bonfanti
DOI:10.1016/j.tetlet.2019.151369
日期:2020.1
A novel reaction giving easy access to 5-bromopyrimidines via the cyclization of 1,2-dibromoenones and amidines is described.
描述了一种新颖的反应,该反应可通过1,2-二溴代烯酮和cycl的环化轻松获得5-溴嘧啶。
Highly regioselective palladium-mediated synthesis of stereoisomerically pure (Z)- and (E)-alkyl 2-bromo-3-(hetero)arylpropenoates
作者:Fabio Bellina、Adriano Carpita、Massimo De Santis、Renzo Rossi
DOI:10.1016/0040-4039(94)85040-2
日期:1994.9
Stereoisomericallypure (Z)- and (E)-alkyl2-bromo-3-(hetero)arylpropenoates, (Z)- and (E)-2, have been efficiently and selectively prepared by Pd(0)-mediated cross-coupling reaction between (hetero)arylzinc halides, 5, and easily available (Z)- and (E)-alkyl 2,3-dibromopropenoates, (Z)- and (E)-4, respectively. Compounds (Z)- and (E)-2 serve as useful precursors to stereoisomericallypure trisubstituted
Total Synthesis of Enantiopure Pyrrhoxanthin: Alternative Methods for the Stereoselective Preparation of 4-Alkylidenebutenolides
作者:Belén Vaz、Leticia Otero、Rosana Álvarez、Ángel R. de Lera
DOI:10.1002/chem.201301873
日期:2013.9.23
A new stereocontrolled total synthesis of the configurationally labile C37‐norcarotenoid pyrrhoxanthin in enantiopure form has been completed. A highlystereoselective Horner–Wadsworth–Emmons (HWE) condensation of a C17‐allylphosphonate and a C20‐aldehyde was used as the last conjunctive step. Both a Sonogashira reaction to form the C17‐phosphonate and the final HWE condensation proved to be compatible
allowing the isolation and identification of a series of polyhaloethyl acetates and acrylates. The recognition of acetone and polyhaloacetones in these extracts suggests biological halogenations occur which result in haloformreactions.
对新鲜 Asparagopsis taxformis 和 A. armata 进行乙醇提取,然后进行戊烷分配,可分离出一系列卤代甲烷,其中包括 MeI、CHCl3 和 CCl4。在这些提取条件下,很容易发生酯化反应,从而可以分离和鉴定一系列多卤代乙酸乙酯和丙烯酸酯。这些提取物中丙酮和多卤代丙酮的识别表明发生了导致卤仿反应的生物卤化。