Enantioselective Scandium-Catalyzed Vinylsilane Additions: A New Approach to the Synthesis of Enantiopure β,γ-Unsaturated α-Hydroxy Acid Derivatives
作者:David A. Evans、Yimon Aye
DOI:10.1021/ja063878k
日期:2006.8.1
The development of the Lewis acid-catalyzed alkenylation using trimethylvinylsilanes is described. Both aliphatic and aromatic vinylsilanes were effective nucleophiles at room temperature affording chiral allylic alcohol products in excellent enantioselectivities (97 → 99% ee) and in moderate to good yields (45−99%). Complete retention of vinysilane geometry was observed where applicable.
Direct coupling of alcohols with alkenylsilanes catalyzed by indium trichloride or bismuth tribromide
作者:Yoshihiro Nishimoto、Masayuki Kajioka、Takahiro Saito、Makoto Yasuda、Akio Baba
DOI:10.1039/b816072d
日期:——
Indium halides or bismuth halides catalyzed the coupling of various alcohols with alkenylsilanes to give the corresponding alkenes stereospecifically without any other activators.
Stereoselective Alkyne Hydrogenation by using a Simple Iron Catalyst
作者:Bernhard J. Gregori、Felix Schwarzhuber、Simon Pöllath、Josef Zweck、Lorena Fritsch、Roland Schoch、Matthias Bauer、Axel Jacobi von Wangelin
DOI:10.1002/cssc.201900926
日期:2019.8.22
stereoselective hydrogenation of alkynes constitutes one of the key approaches for the construction of stereodefined alkenes. The majority of conventional methods utilize noble and toxic metal catalysts. This study concerns a simple catalyst comprised of the commercial chemicals iron(II) acetylacetonate and diisobutylaluminum hydride, which enables the Z-selective semihydrogenation of alkynes under near ambient
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。
Stereoselective Chromium‐Catalyzed Semi‐Hydrogenation of Alkynes
作者:Bernhard J. Gregori、Michal Nowakowski、Anke Schoch、Simon Pöllath、Josef Zweck、Matthias Bauer、Axel Jacobi von Wangelin
DOI:10.1002/cctc.202000994
日期:2020.11.5
very little applications as hydrogenation catalysts. Here, we report a Cr‐catalyzed semi‐hydrogenation of internal alkynes to the corresponding Z‐alkenes with good stereocontrol (up to 99/1 for dialkyl alkynes). The catalyst comprises the commercial reagents chromium(III) acetylacetonate, Cr(acac)3, and diisobutylaluminium hydride, DIBAL−H, in THF. The semi‐hydrogenation operates at mild conditions
Silicon in organic synthesis. Stereoselective synthesis of some insect sex pheromones
作者:T.H. Chan、K. Koumaglo
DOI:10.1016/0022-328x(85)87361-7
日期:1985.4
stereo-selectively the γ-product with trans-stereochemistry at the double bond. The trans-vinylsilanes are transformed stereoselectively to Z-vinyl iodides. Coupling of the vinyl iodides with organometallic reagents gives Z-alkenes. This approach has been applied to the synthesis of several insect sexpheromones.