Stereoselective synthesis of cationic heterobidentate C(NHC)/SR rhodium(I) complexes using stereodirecting N,N-dialkylamino groups
作者:Abel Ros、Manuel Alcarazo、David Monge、Eleuterio Álvarez、Rosario Fernández、José M. Lassaletta
DOI:10.1016/j.tetasy.2010.04.041
日期:2010.6
The synthesis of two different types of chiral C/S ligands based upon N-(N,N-dialkylamino)-substituted N-heterocyclic carbenes and thioether functionalities, along with their neutral [RhCl(CNH)(COD)] and cationic [Rh(I)(NHC/S)(COD)]+ complexes, has been accomplished. (S)-2-[(Phenylthio)methyl]pyrrolidine, carrying the thioether moiety, and (2S,5S)-2,5-diphenylpyrrolidine, combined with a thioether
基于N-(N,N-二烷基氨基)-取代的N-杂环卡宾和硫醚官能团及其中性[RhCl(CNH)(COD)]和阳离子[Rh]的两种不同类型的手性C / S配体的合成(I)(NHC / S)(COD)] +配合物已完成。(S)-2-[((苯硫基)甲基]吡咯烷,带有硫醚部分,和(2 S,5 S)-2,5-二苯基吡咯烷与硫醚官能化的侧链结合,被作为潜在的立体定向基团进行了研究。只有后者在中性络合物的形成中提供了高选择性,从而导致新形成的,构型稳定的C(NHC)-Rh键具有单一的对映体(de> 98%)。然而,相应的阳离子型[Rh(I)(NHC / S)(COD)] +配合物的合成分别导致形成单个(R a,S S)和(S a,S S)非对映异构体,每种情况下四种可能的络合物的[[(R a / S a)C(NHC)–Rh轴与(S s / R s)通过协调形成立体异构S中心]。对于脯氨酸衍生物,(R a /