Aqueous Sodium Hydroxide Promoted Cross-Coupling Reactions of Alkenyltrialkoxysilanes under Ligand-Free Conditions
作者:Emilio Alacid、Carmen Nájera
DOI:10.1021/jo702570q
日期:2008.3.1
alkenyltrialkoxysilanes with aryl iodides, bromides, and chlorides are performed on water using sodium hydroxide as activator at 120 °C under normal or microwave heating. This process occurs in the presence of Pd(OAc)2 or 4-hydroxyacetophenone oxime-derived palladacycle 1 as precatalysts under ligand-free conditions with low Pd loadings (0.01−1 mol %) and using tetra-n-butylammonium bromide as additive. Different
diverse range of functional groups including silyl protections. The silicon residue is readily recovered and reused on a gram-scale synthesis. Intramolecular coordination of a proximal hydroxyl group is considered to efficiently form pentacoordinate silicates having a transferablegroup possibly at an axial position and, thus, responsible for the cross-coupling reaction under conditions significantly
通过使用保护的[2-(羟甲基)苯基]二甲基硅烷,通过铂或钌催化剂催化的炔烃的立体和区域选择性氢化硅烷化反应,制备高度稳定的烯基[2-(羟甲基)苯基]二甲基硅烷。通过与烯基格氏试剂的开环反应,环状甲硅烷基醚1,1-二甲基-2-氧杂-1-silaindan也用作烯基硅烷的原料。在使用K 2 CO 3的反应条件下,所得烯基硅烷与各种芳基和烯基碘化物进行交叉偶联反应以高度区域性和立体定向方式在35–50°C下作为碱。该反应可耐受各种官能团,包括甲硅烷基保护基。硅残留物很容易被回收并以克级合成法再利用。近端羟基的分子内配位被认为有效地形成了可能在轴向位置具有可转移基团的五配位硅酸盐,因此,在比基于硅的反应所报道的条件温和得多的条件下,负责交叉偶联反应。
ZrCl2(η-C5Me5)2-AlHCl2·(THF)2: efficient hydroalumination of terminal alkynes and cross-coupling of the derived alanes
作者:Philip Andrews、Christopher M. Latham、Marc Magre、Darren Willcox、Simon Woodward
DOI:10.1039/c2cc37537k
日期:——
with exceptional chemo-, regio- and stereoselectivity under efficient ZrCl(2)(eta-C(5)Me(5))(2) catalysis (2-5 mol%). The resulting vinyl alanes undergo palladium cross-coupling with a wide range of sp(2) electrophiles (aryl, heteroaryl and vinylhalides/pseudohalides) in good to excellent yields.
Alkenyl- and Aryl[2-(hydroxymethyl)phenyl]dimethylsilanes: An Entry to Tetraorganosilicon Reagents for the Silicon-Based Cross-Coupling Reaction
作者:Yoshiaki Nakao、Hidekazu Imanaka、Akhila K. Sahoo、Akira Yada、Tamejiro Hiyama
DOI:10.1021/ja051281j
日期:2005.5.1
Alkenyl- and aryl[2-(hydroxymethyl)phenyl]dimethylsilanes, highly stable tetraorganosilicon reagents, are found to react with aryl and alkenyl iodides in the presence of a palladium catalyst and K2CO3 as a base, significantly milder conditions compared with those ever reported for the silicon-based cross-coupling reactions. The reaction tolerates a wide range of functional groups, including silyl protectors, and allows a gram-scale synthesis to recover and reuse the silicon residue.
TAMAO, KOHEI;KOBAYASHI, KENJI;ITO, YOSHIHIKO, TETRAHEDRON LETT., 30,(1989) N4, C. 6051-6054