USE OF LANTHANIDE(III) IONS AS CATALYSTS FOR THE REACTIONS OF AMINES WITH NITRILES
USE OF LANTHANIDE(III) IONS AS CATALYSTS FOR THE REACTIONS OF AMINES WITH NITRILES
复制标题
DOI：
10.1021/jo00382a009
复制
发表时间：
1987-03-20
影响因子：
3.6
通讯作者：
MILLER, JL
中科院分区：
文献类型：
--
作者：
FORSBERG, JH;SPAZIANO, VT;MILLER, JL
催化量的镧系元素 (III) 膨胀促进胺和腈之间的反应，产生多种产物。即使在胺存在的情况下，Ln3+ 离子也会在较大的胺：Ln3+ 摩尔比下活化弱配位腈，从而与 Ln3+ 离子形成热力学稳定的络合物。涉及伯单胺和二胺的反应似乎是通用的，并且分别为，'-二取代的脒(2)和环脒(4)提供了可行的合成路线。当使用过量的腈进行反应时，在一些系统中观察到对称取代的三嗪（8或9）作为副产物。脂环族仲胺或二甲胺与乙腈反应生成嘧啶(6)和2,4,6-三甲基-s-三嗪(8)。已经提出了两种制备三嗪的路线，一种涉及氨与腈的反应，第二种涉及脒（1或5）与腈的反应。 Ln3+离子在反对腈配位的条件下活化腈的能力归因于源自N-供体的Ln3+络合物的不稳定性。之前我们报道了镧系元素(III)高氯酸盐催化单齿环状仲胺和乙腈之间的反应，得到N-取代的乙脒(5)或4-取代的-2， 6-二甲基嘧啶(6)。 1 值得注意的是，后一个例子代表了 Ln3+ 离子催化反应导致碳-碳键形成的第一个例子。 Ln3+离子在这些系统中的催化活性非常令人惊讶，因为乙腈通常用作制备镧系元素的N-供体配合物的溶剂。 2 尽管已证明腈与过渡金属离子或其他路易斯酸的配位可促进与胺的反应，从而生成脒，但 3 与我们使用 Ln3+ 催化剂获得的杂环化合物类似的杂环化合物的形成尚未见报道。此外，我们还发现，相对于有机试剂，Ln3+离子在1 mol%的水平下可有效活化腈分子，而与过渡金属离子的反应是通过使用化学计量的催化剂进行的。 4
Catalytic amounts of lanthanide (III) inflates promote reactions betweenamines and nitriles leading to a variety of products. The Ln3+ ionsactivate weakly coordinating nitriles at large amine: Ln3+ mole ratios, even in the presence of amines that form thermodynamically stable complexes with Ln3+ ions. The reactions involving primary monoamines and diamines appear to be general and provide a viable synthetic route to,'-disubstituted amidines (2) andcyclic amidines (4), respectively. Symmetrically substituted triazines (8 or 9) are observed as byproducts in some of these systems whenthe reactions are carried out by using excess nitrile. Secondary alicyclic amines or dimethylamine reacts with acetonitrile to yield pyrimidines (6) and2, 4, 6-trimethyl-s-triazine (8). Two routes to triazine have been proposed, one involving the reaction of ammonia with the nitrile and the second involving the reaction of an amidine (1 or 5) with the nitrile. The ability of Ln3+ ions toactivate nitriles under conditions that oppose nitrile coordination is attributed to the lability of Ln3+ complexesderived from N-donors.Previously we reported that lanthanide (III) perchlorate salts catalyze reactions between unidentate cyclic sec-ondary amines and acetonitrile to give N-substituted acetamidines (5) or 4-substituted-2, 6-dimethylpyrimidines (6). 1 It is noteworthy that the latter instance represented the first example of a Ln3+ ion catalyzed reaction resulting in the formation of a carbon-carbon bond. Catalytic ac-tivity of the Ln3+ ions in these systems was quite sur-prising, since acetonitrile is commonly used as a solvent to prepare N-donor complexes of the lanthanides. 2 Al-though coordination of a nitrile to transition metal ions or other Lewisacids has been shown to promote reactions with amines leading to amidines, 3 formation of heterocyclic compounds analogous to those we have obtained using Ln3+ catalysts has not been reported. Furthermore, we have found that Ln3+ ions effectively activate nitrile molecules at levels of 1 mol% relative to the organic reagents, whereas reactions with transition metal ions are carried out by using a stoichiometric amount of catalyst. 4