Enantioselective Mukaiyama-Aldol Reaction of Pyruvates and 1-Phenyl- 1-trimethylsilyloxyethene Catalyzed by Lanthanide/Pybox Complexes
作者:Giovanni Desimoni、Giuseppe Faita、Francesca Piccinini、Marco Toscanini
DOI:10.1002/ejoc.200600716
日期:2006.12
1-phenyl-1-trimethylsilyloxyethene (1) and three pyruvates (2a–c) is catalyzed by the lanthanide triflate complexes of(4S,5S)-2,6-bis[5-phenyl-4-(triisopropylsilyloxy)methyl-1,3-oxazolin-2-yl]pyridine (3). The best catalysts are the LuIII- and ScIII-based complexes that give high yields of (S)-4a–c and enantiomeric excesses up to 99.5 %. The LaIII-based complex favors the formation of the opposite enantiomer
1-苯基-1-三甲基甲硅烷氧基乙烯 (1) 和三种丙酮酸 (2a-c) 之间的对映选择性 Mukaiyama-醛醇反应由 (4S,5S)-2,6-双 [5-苯基-4 的镧系元素三氟甲磺酸盐络合物催化-(三异丙基甲硅烷氧基)甲基-1,3-恶唑啉-2-基]吡啶(3)。最好的催化剂是基于 LuIII 和 ScIII 的配合物,它们可以提供高产率 (S)-4a-c 和高达 99.5% 的对映体过量。基于 LaIII 的配合物有利于形成相反的对映异构体 [(R)-4c 的 77% ee]。提出了立体化学结果的基本原理。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)