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。
A method for the carboallylation of electron-deficient alkenes with tetraorganosilicon reagents and allylic carbonates based on Pd/Cu catalysis has been developed. This method affords a wide range of structurally diverse carbon skeletons from readily available starting materials, and tolerates various functional groups.
The title reaction is found to proceed in the presence of a rhodium/diene catalyst. Variously substituted diarylmethylamines and allylamines having an N-arenesulfonyl protection are obtained in good yields, which are important building blocks in organic synthesis.
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.
Catalytic Asymmetric Synthesis of Allylsilanes through Rhodium/Chiral Diene-Catalyzed 1,4-Addition of Alkenyl[2-(hydroxymethyl)phenyl]dimethylsilanes
A new synthetic method of chiral allylsilanes has been developed through a rhodium-catalyzed asymmetric 1,4-addition of alkenyl[2-(hydroxymethyl)phenyl]dimethylsilanes to beta-silyl alpha,beta-unsaturated ketones. By employing (S,S)-Ph-bod* as a ligand, a range of alkenyl nucleophiles have been installed to these substrates in high yield and enantiomeric excess. The resulting allylsilanes can be used for stereoselective intramolecular allylation reactions to control two contiguous tertiary and quaternary stereocenters.
Organo[2-(hydroxymethyl)phenyl]dimethylsilanes as Mild and Reproducible Agents for Rhodium-Catalyzed 1,4-Addition Reactions
achievement of the corresponding enantioselective transformations using the tetraorganosilicon reagents, providing the silicon-based approach to opticallyactiveketones and substituted piperidones that serve as synthetic intermediates of pharmaceuticals. A rhodium alkoxide species is suggested to be responsible for a transmetalation step on the basis of the observed kinetic resolution of a racemic chiral phenylsilane