钯（II）促进的吡咯啉N-氧化物与有机腈的[2 + 3]环加成反应。（Δ⁴-1,2,4-恶二唑啉）-钯（II）配合物在铃木-宫浦反应中的应用。

Pd(II)-promoted [2 + 3] cycloaddition of pyrroline N-oxide to organonitriles. Application of (Delta(4)-1,2,4-oxadiazoline)-Pd(II) complexes in the Suzuki-Miyaura reaction.

作者信息

Lasri Jamal, Guedes da Silva M Fátima C, Kopylovich Maximilian N, Mukhopadhyay Suman, Charmier M Adília Januário, Pombeiro Armando J L

机构信息

Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Lisbon, Portugal.

出版信息

Dalton Trans. 2009 Mar 28(12):2210-6. doi: 10.1039/b813996b. Epub 2009 Feb 6.

DOI:10.1039/b813996b

PMID:19274300

Abstract

[2 + 3] Cycloaddition reactions of the organonitriles RCN 1 (R = Me (1a), Et (1b), p-IC(6)H(4) (1c), p-BrC(6)H(4) (1d), p-ClC(6)H(4) (), p-FC(6)H(4) (1e)) with the pyrroline N-oxide (-)O(+)[upper bond 1 start]N[double bond, length as m-dash]CHCH(2)CH(2)C[upper bond 1 end]Me(2) in the presence of PdCl(2) proceed at room temperature for 12 h and allow the isolation of the corresponding palladium(ii) complexes trans-[PdCl(2){[upper bond 1 start]N[double bond, length as m-dash]C(R)O[lower bond 1 start]NCupper bond 1 endCH(2)CH(2)C[lower bond 1 end]Me(2)}(2)] 3a-3f containing fused bicyclic Delta(4)-1,2,4-oxadiazoline ligands, in good to excellent yields (75-90%). Treatment of trans-[PdCl(2)(EtCN)(2)] with the nitrone in acetone or propionitrile at room temperature affords, in good yield, (R = Et), confirming that complexes 3 are formed via nitrile activation by coordination. These reactions proceed with high diastereoselectivity and afford mixtures of enantiomers, due to the rigid conformation (E) of the cyclic nitrone 2. The oxadiazolines [upper bond 1 start]N[double bond, length as m-dash]C(R)O[lower bond 1 start]NCupper bond 1 endCH(2)CH(2)C[lower bond 1 end]Me(2) (R = Et (4b), p-FC(6)H(4) (4f)) are liberated upon reaction of complexes 3b,3f with a diphosphine (dppe). During the liberation of , the complex trans-[PdCl(2){[upper bond 1 start]N[double bond, length as m-dash]C(NHCOC(6)H(4)F-4)CH(2)CH(2)C[upper bond 1 end]Me(2)}(2)] was formed in a minor amount upon N-O bond cleavage of the oxadiazoline ring to give a pyrrolylbenzamide species coordinated by the N-atom of the pyrrolyl moiety. The compounds were characterized by IR, (1)H and (13)C NMR spectroscopies, ESI-MS, elemental analyses and, in the cases of 3b, 3d and 5, also by X-ray diffraction analyses. Complexes 3b and 3f show a high catalytic activity towards the microwave-assisted Suzuki-Miyaura cross-coupling reaction in aqueous medium, achieving a TON value of 2.7 x 10(5) and a TOF value of 1.1 x 10(6) h(-1).

摘要

在氯化钯存在下，有机腈RCN 1（R = 甲基（1a）、乙基（1b）、对碘苯基（1c）、对溴苯基（1d）、对氯苯基（）、对氟苯基（1e））与吡咯啉N - 氧化物（-）O(+)[上键1起始]N[双键，长度如中破折号]CHCH(2)CH(2)C[上键1结束]Me(2)进行[2 + 3]环加成反应，在室温下反应12小时，可分离得到相应的钯（II）配合物反式-[PdCl(2){[上键1起始]N[双键，长度如中破折号]C(R)O[下键1起始]NC上键1结束CH(2)CH(2)C[下键1结束]Me(2)}(2)] 3a - 3f，其含有稠合双环Δ(4)-1,2,4 - 恶二唑啉配体，产率良好至优异（75 - 90%）。在室温下，将反式-[PdCl(2)(乙腈)(2)]与硝酮在丙酮或丙腈中反应，可高产率得到（R = 乙基），证实配合物3是通过腈的配位活化形成的。由于环状硝酮2的刚性构象（E），这些反应具有高非对映选择性，并产生对映体混合物。在配合物3b、3f与二膦（dppe）反应时，恶二唑啉[上键1起始]N[双键，长度如中破折号]C(R)O[下键1起始]NC上键1结束CH(2)CH(2)C[下键1结束]Me(2)（R = 乙基（4b）、对氟苯基（4f））被释放出来。在释放过程中，恶二唑啉环的N - O键断裂时会少量形成配合物反式-[PdCl(2){[上键1起始]N[双键，长度如中破折号]C(NHCOC(6)H(4)F - 4)CH(2)CH(2)C[上键1结束]Me(2)}(2)]，得到由吡咯基部分的N原子配位的吡咯基苯甲酰胺物种。这些化合物通过红外光谱、(1)H和(13)C核磁共振光谱、电喷雾质谱、元素分析进行表征，对于3b、3d和5，还通过X射线衍射分析进行表征。配合物3b和3f在水介质中对微波辅助的铃木 - 宫浦交叉偶联反应显示出高催化活性，TON值达到2.7×10(5)，TOF值达到1.1×10(6) h(-1)。