炔烃的立体选择性加氢构成构造立体烯烃的关键方法之一。大多数常规方法利用贵金属和有毒金属催化剂。这项研究涉及一种由工业化学品乙酰丙酮铁(II)和氢化二异丁基铝组成的简单催化剂,该催化剂能够在接近环境条件(1-3 bar H2、30°C,5 mol%[Fe] )。既不需要复杂的催化剂制备也不需要添加配体。机理研究(动力学中毒,X射线吸收光谱法,TEM)强烈表明了小铁簇和颗粒催化剂的运行。
The four isomeric 5, 10-pentadecadienals 1, 2, 3 and 4 were prepared by stereo-selective routes from acetylenic precursors. Two of them, 2 and 4, were also made by Wittig reaction from 2-hydroxytetrahydropyran (29). 2-Hydroxytetrahydropyran (29) yields (Z)-5-alkenols efficiently by Wittig reaction, and (Z)-4-hexenol was similarly made from 2-hydroxytetrahydrofuran (66).
Intramolecular zinc-ene reactions of alkynes; preparation of 1,5-annulated 4-methylenecyclopentenes
作者:Jaap van der Louw、Juul L. van der Baan、Corine M.D. Komen、Adri Knol、Franciscus J.J. de Kanter、Friedrich Bickelhaupt、Gerhard W. Klumpp
DOI:10.1016/s0040-4020(01)89858-6
日期:1992.1
Intramolecular Type I zinc-enereaction of 3-(alk-m-ynyl)-2-(methoxymethyl)-2-propenylzinc bromides 2 (m = 4,5,6) gave five-, six- and seven-membered carbometallation product 3, which on Pd(0)-catalyzed cyclization were converted to 1,5-annulated 4-methylenecyclopentenes 4. Preparation of 4-methylenecyclopentenes by intramolecular Type II zinc-enereactions of 2-(alk-m-ynyloxymethyl)-2-alkenylzinc