Synthesis of (Z)-1-aryl-2-(germyl)-1-(stannyl)ethenes and the related ethenes, precursors to stereodefined germylethenes, via Pd(dba)2–P(OCH2)3CEt-catalyzed germastannation of acetylenes in THF
摘要:
(Z)-1-Aryl-2-(germyl)-1-(stannyl)ethenes are synthesized in high yields by the addition of tributyl(triethylgermyl)stannane to arylacetylenes catalyzed by a specific combination catalyst, Pd(dba)(2) and 4-ethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane, in tetrahydrofuran. Ethynylthiophene and 2-methyl-3-butyn-2-ol are also subject to the germastannation to afford the respective adducts in high yields. In addition, the J(Sn-H) and C-13-NMR data for their adducts are presented. (C) 2001 Elsevier Science B.V. All rights reserved.
Described are methods of forming protected boronic acids that provide in a manner that is straightforward, scalable, and cost-effective a wide variety of building blocks, such as building blocks containing complex and/or pharmaceutically important structures, and/or provide simple or complex protected organoboronic acid building blocks. A first method includes reacting an imino-di-carboxylic acid and an organoboronate salt. A second method includes reacting a N-substituted morpholine dione and an organoboronic acid.
(Triethylgermyl)tributylstannane reacts metal-selectively with allylic halides at room temperature (r.t.) in the presence of tris(dibenzylideneacetone)dipalladium, Pd2(dba)3CHCl3, to provide an alternative route to allylgermanes. (Dimethylphenylgermyl)tributylstannane regio- and stereoselectively reacts more readily with allylic halides than (triethylgermyl)tributylstannane affording the corresponding allylgermanes
A Simple and General Platform for Generating Stereochemically Complex Polyene Frameworks by Iterative Cross-Coupling
作者:Suk Joong Lee、Thomas M. Anderson、Martin D. Burke
DOI:10.1002/anie.201004911
日期:2010.11.15
Not so complex: A novel iterative cross‐coupling strategy provides access to useful building blocks that enable the simple preparation of complexpolyene natural‐product motifs in all possible stereoisomeric forms. The method was used to synthesize the polyene core of vacidin A (see structure).
不那么复杂:一种新颖的迭代交叉偶联策略提供了有用的构建模块,能够以所有可能的立体异构形式简单地制备复杂的多烯天然产物基序。该方法用于合成 vacidin A 的多烯核(见结构)。
Alternative Synthesis of (<i>Z</i>)-1-Aryl-1-(tributylstannyl)-2-(triethylgermyl)ethenes and the Unprecedented Germyl 1,2-Migration during the Destannylation of the Adducts
作者:Taichi Nakano、Yoshiya Senda、Takashi Miyamoto
DOI:10.1246/cl.2000.1408
日期:2000.12
A specific combination catalyst, Pd(dba)2 and 4-ethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane, effectively catalyzed the addition of tributyl(triethylgermyl)stannane to arylacetylenes in tetrahydrofuran to give (Z)-1-aryl-2-(germyl)-1-(stannyl)ethenes in high yields. The (Z)-1-aryl-2-(germyl)-1-(stannyl)ethenes were subject to the unprecedented germyl 1,2-migration during the destannylation using HI / TBAI in toluene to produce 1-aryl-1-(germyl)ethenes in high yields.
Synthesis of (Z)-1-aryl-2-(germyl)-1-(stannyl)ethenes and the related ethenes, precursors to stereodefined germylethenes, via Pd(dba)2–P(OCH2)3CEt-catalyzed germastannation of acetylenes in THF
(Z)-1-Aryl-2-(germyl)-1-(stannyl)ethenes are synthesized in high yields by the addition of tributyl(triethylgermyl)stannane to arylacetylenes catalyzed by a specific combination catalyst, Pd(dba)(2) and 4-ethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane, in tetrahydrofuran. Ethynylthiophene and 2-methyl-3-butyn-2-ol are also subject to the germastannation to afford the respective adducts in high yields. In addition, the J(Sn-H) and C-13-NMR data for their adducts are presented. (C) 2001 Elsevier Science B.V. All rights reserved.