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首页> 外文期刊>Chemistry: A European journal >Catalytic addition of amine N-H bonds to carbodiimides by half-sandwich rare-earth metal complexes: Efficient synthesis of substituted Guanidines through amine protonolysis of rare-earth metal guanidinates
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Catalytic addition of amine N-H bonds to carbodiimides by half-sandwich rare-earth metal complexes: Efficient synthesis of substituted Guanidines through amine protonolysis of rare-earth metal guanidinates

机译：半三明治稀土金属配合物催化碳二亚胺上胺N-H键的催化加成：稀土金属胍盐的胺质子分解，可高效合成取代的胍

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Reaction of [Ln(CH2SiMe3)(3)(thf)(2)] (Ln=Y, Yb, and Lu) with one equivalent of Me2Si(C5Me4H)NHR' (R'-Ph, 2,4,6-Me3C6H2, tBu) affords straightforwardly the corresponding half-sandwich rare-earth metal alkyl complexes [{Me2Si(C5Me4)(NR')}Ln(CH2SiMe3)(thf)(n)] (1: Ln Y, R' = Ph, n - 2; 2: Ln = Y, R' C6H2Me3-2,4,6, n = 1; 3: Ln Y, R' tBu, n = 1; 4: Ln = Yb, R' Ph, n 2; 5: Ln = Lu, R' = Ph, n = 2) in high yields. These complexes, especially the yttrium complexes 1-3, serve as excellent catalyst precursors for the catalytic addition of various primary and secondary amines to carbodiimides, efficiently yielding a series of guanidine derivatives with a wide range of substituents on the nitrogen atoms. Functional groups such as C=N, C=CH, and aromatic C-X (X: F, Cl, Br, I) bonds can survive the catalytic reaction conditions. A primary amino group can be distinguished from a secondary one by the catalyst system, and therefore, the reaction of 1,2,3,4-tetrahydro-5-aminoisoquinoline with iPrN=C=NiPr can be achieved stepwise first at the primary amino group to selectively give the monoguanidine 38, and then at the cyclic secondary amino unit to give the biguanidine 39. Some key reaction intermediates or true catalyst species, such as the amido complexes [{Me2Si(C5Me4)(NPh))Y(NEt2)(thf)(2)] (40) and [(Me2Si(C5Me4)(NPh))Y(NHC6H4Br4)(thf)(2)] (42), and the guanidinate complexes [{Me2Si(C5Me4)(NPh)}Yj{PrNC(NEt2)(NiPr))(thf)] (41) and [{Me2Si(C5Me4)(NPh)}Y[iPrN)C(NC6H4Br-4)- (NHiPr))(thf)] (44) have been isolated and structurally characterized. Reactivity studies on these complexes suggest that the present catalytic formation of a guanidine compound proceeds mechanistically through nucleophilic addition of an amido species, formed by acid-base reaction between a rare-earth metal alkyl bond and an amine N-H bond, to a carbodiimide, followed by amine protonolysis of the resultant guanidinate species.
机译：[Ln（CH2SiMe3）（3）（thf）（2）]（Ln = Y，Yb和Lu）与一当量的Me2Si（C5Me4H）NHR'（R'-Ph，2,4,6-Me3C6H2 ，tBu）直接提供相应的半三明治稀土金属烷基络合物[{Me2Si（C5Me4）（NR'）} Ln（CH2SiMe3）（thf）（n）]（1：Ln Y，R'= Ph，n -2; 2：Ln = Y，R'C6H2Me3-2,4,6，n = 1; 3：Ln Y，R'tBu，n = 1; 4：Ln = Yb，R'Ph，n 2; 5 ：Ln ＝ Lu，R′＝ Ph，n ＝ 2）高产率。这些配合物，特别是钇配合物1-3，是用于将各种伯胺和仲胺催化加成至碳二亚胺的极好的催化剂前体，有效地产生了一系列在氮原子上具有广泛取代基的胍衍生物。诸如C = N，C = CH和芳族C-X（X：F，Cl，Br，I）键之类的官能团可以在催化反应条件下生存。通过催化剂体系可以将伯氨基与仲氨基区分开，因此，1,2,3,4-四氢-5-氨基异喹啉与iPrN = C = NiPr的反应可以首先在伯氨基上逐步实现基团选择性地产生单胍38，然后在环状仲氨基单元上产生双胍39。一些关键的反应中间体或真正的催化剂种类，例如酰胺络合物[{Me2Si（C5Me4）（NPh））Y（NEt2） （thf）（2）]（40）和[（Me2Si（C5Me4）（NPh））Y（NHC6H4Br4）（thf）（2）]（42），以及胍盐配合物[{Me2Si（C5Me4）（NPh）} Yj {PrNC（NEt2）（NiPr））（thf）]（41）和[{Me2Si（C5Me4）（NPh）} Y [iPrN）C（NC6H4Br-4）-（NHiPr））（thf）]（44）已被隔离并在结构上进行了表征。对这些络合物的反应性研究表明，胍化合物的当前催化形成过程是通过亲核加成酰胺类而进行的，该酰胺类是由稀土金属烷基键和胺NH键之间的酸碱反应形成的，然后是碳二亚胺。通过胺质子分解得到的胍盐。

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