【作者】 胡泓梵；

【导师】 崔春明；

【作者基本信息】 南开大学 ， 有机化学， 2013， 博士

【摘要】 本论文合成并表征了硅桥联吡咯茂配体、三齿脒基亚胺配体以及N-杂环卡宾配体的异配型钙及稀土金属有机化合物,并对其反应性及催化性能进行了研究。此外,研究了2,1-苯并氮杂硼咯的合成方法,并对其反应性进行了探索。主要结果如下：1.合成了两个硅桥联的吡咯茂配体[(C5Me4H)-SiMe2-(NC4H4)](L1H)和[(C5Me4H)-SiMe2-(C4H3NMe)](L2H)。该配体与Ca[N(SiMe3)2]2(THF)2反应可以得到异配型的钙胺基化合物L1Ca{N(SiMe3)2}(2)和L2Ca{N(SiMe3)2}(8)。这两个钙化合物的稳定性不好,其在溶液状态下容易发生配体交换反应生成均配型化合物。此外,配体L2H与Yb[N(SiMe3)2]2(THF)2反应未能分离得到单一的异配型化合物。2.合成了大位阻的三齿脒基配体[2-{NHC(Ph)NAr}C6H4CHNAr](L3H,Ar=2,6-iPr2C6H3),其与M[N(SiMe3)2]2(THF)2(M=Ca,Yb)反应得到异配型的化合物[L3M{N(SiMe3)2}(THF)](13,M=Ca;14,M=Yb),二者具有非常好的热稳定性。化合物13及14在温和的条件下对烯烃和炔烃的分子间膦氢化反应具有很高的催化活性,得到反马氏加成的产物。对于共轭二烯,两个催化剂均得到1,4-加成的产物；对于炔烃,Ca催化体系倾向于反式加成而Yb催化体系倾向于顺式加成。3.通过N-杂环卡宾[C(NRCR’)2](IiPr,R=iPr,R’=Me;IMes,R=2,4,6-Me3C6H2,R’=H;IMe4,R=R’=Me)与M[N(SiMe3)2]2(THF)2(M=Ca, Yb)反应,合成了钙及镱的金属卡宾加合物IiPrCa[N(SiMe3)2]2(17)、 IMesCa[N(SiMe3)2]2(18)、(IMe4)2Ca[N(SiMe3)2]2(19)、(IMe4)2Yb[N(SiMe3)2]2(21)以及(IMe4)(IiPr)Yb[N(SiMe3)2]2(22),并对其反应性及催化性能进行了研究。实验发现,卡宾-钙胺基加合物与Ph2PH反应时,卡宾配体从钙金属中心脱落。相反,卡宾-镱胺基加合物与Ph2PH反应生成卡宾稳定的镱的双膦化合物(IMe4)3Yb(PPh2)2(24)。NHC-Yb加合物21在温和条件下对烯烃以及炔烃的分子间的膦氢化反应具有非常高的催化活性,但共轭烯烃以及炔烃的反应选择性不理想。此外,该催化体系最大的优点在于,催化反应转化完全以后可以实现均相催化剂的回收。4.用2当量的碱金属还原亚胺-硼溴化合物[o-C6H4(CH=NR)B(Ph)Br](26,R=2,6-iPr2C6H3;27,R=tBu),得到了相应的2,1-苯并氮杂硼咯负离子[o-C6H4{B(Ph)N(R)CH}]-[M]+(THF)n(33-36,R=2,6-iPr2C6H3,tBu;M=Li,K;n=1-4),这些化合物与亲电试剂反应得到1,2,3-三取代的2,1-苯并氮杂硼咯烷化合物37-41。此外,用1当量的碱金属还原化合物26和27,发生了C-C键偶联生成二聚的2,1-苯并氮杂硼咯烷化合物[o-C6H4{B(Ph)N(R)CH}]2(42, R=2,6-iPr2C6H3;43,R=tBu),均为非对映异构体混合物。实验证明,在催化量的碱的存在下,可以实现单向的非对映异构化反应,由内消旋体转化为外消旋体。此外,在适当的胺基K盐或Li盐催化下,二聚的2,1-苯并氮杂硼咯烷43可以对甲苯进行活化生成化合物[o-C6H4{B(Ph)N(tBu)CH(CH2Ph)}](44)和[o-C6H4{B(Ph)N(tBu)CH2}](45)。通过异构化和C-H键活化反应的机理研究发现,异构化反应为C-C键“异裂-重组”的机理。甲苯活化反应是通过C-C键异裂产生的正负离子对来进行的,其中,K盐或Li盐的作用主要是提供碱性条件以及作为抗衡离子稳定活性中间体。更多还原

【Abstract】 In this dissertation, calcium and rare-earth complexes supported by SiMe2-bridged pyrrolyl-cyclopentadienyl ligand, tridentate imino-amidinate ligand and N-heterocyclic carbenes have been synthesized and characterized. The reactivity and catalytic reactions of these complexes have been investigated. Furthermore, a new synthetic route to2,1-benzazaboroles and2,1-benzazaborolyl anions has been developed, and the reactivity of these compounds have been explored. The details are as follows:1. Two pyrrolyl-cyclopentadienyl ligands [(C5Me4H)-SiMe2-(NC4H4)](L1H) and [(C5Me4H)-SiMe2-(C4H3NMe)](L2H) have been synthesized and characterized. The reactions of the ligands with Ca[N(SiMe3)2]2(THF)2gave heteroleptic calcium amides L1Ca{N(SiMe3)2}(2) and L2Ca{N(SiMe3)2}(8). However, compound2and8are not stable in solution, which readily undergo ligand-exchange to form homoleptic complexes.2. Bulky tridentate imino-amidinate ligand [2-{NHC(Ph)NAr}C6H4CHNAr](L3H, Ar=2,6-iPr2C6H3) was synthesized and characterized. The calcium and ytterbium complexes [L3M{N(SiMe3)2}(THF)](13, M=Ca;14, M=Yb) supported by this ligand were prepared by the reaction of L3H and M[N(SiMe3)2]2(THF)2.13and14show high thermal stability and catalyze intermolecular hydrophosphination of alkenes,1,3-dienes and alkynes with high activity and selectivity under mild conditions. High selective1,4-additions (94-100%) for the conjugated dienes examined were observed with both catalysts. The calcium complex exclusively catalyzes anti-addition to alkynes including terminal alkynes, while the ytterbium complex catalyzes syn-addition in most cases.3. A series of calcium and ytterbium NHC adducts I’PrCa[N(SiMe3)2]2(17), IMesCa[N(SiMe3)2]2(18),(IMe4)2Ca[N(SiMe3)2]2(19),(IMe4)2Yb[N(SiMe3)2]2(21) and (IMe4)(I’Pr)Yb[N(SiMe3)2]2(22) have been prepared by the reaction of [C(NRCR’)2](I’Pr, R=iPr, R’-Me; IMes, R=2,4,6-Me3C6H2, R’=H; IMe4, R=R’=Me) and M[N(SiMe3)2]2(THF)2(M-Ca, Yb). The reactivity studies showed that Ca-NHC adducts are less stable than Yb-NHC adducts. The Yb-NHC adduct21reacted readily with2equivalents of Ph2PH to form NHC-supported ytterbium diphosphide (IMe4)3Yb(PPh2)2(24). In addition,21catalyzes intermolecular hydrophosphination of alkenes and alkynes with high activity under mild conditions. Most importantly, the homogeneous catalyst can be recovered after the catalytic reaction.4. Reduction of imine-chelated boron bromides [o-C6H4(CH=NR)B(Ph)Br](26, R=2,6-iPr2C6H3;27, R=tBu) with2equivalents of alkali metal offered a new pathway to2,1-benzazaborolyl anions [o-C6H4{B(Ph)N(R)CH}]-[M]+(THF)n (33-36, R=2,6-iPr2C6H3,tBu; M=Li, K; n=1-4), which reacted readily with electrophiles to afford1,2,3-trisubstituted2,1-benzazaboroles37-41. Moreover, reduction of the boron bromides with1equivalent of alkali metal resulted in the dimerization of benzazaboroles with the formation of [o-C6H4{B(Ph)N(R)CH}]2(42, R=2,6-iPr2C6H3;43, R=tBu), as the mixture of two diastereoisomers. Interestingly, the mesomeric2,1-benzazaboroles could undergo irreversible diastereomeric isomerization to form the racemic isomer catalyzed by suitable bases. In addition, with the catalysis of nitrogen-containing bases, compound43could activate the sp3C-H bond in toluene to afford compound [o-C6H4{B(Ph)N(/Bu)CH(CH2Ph)}](44) and [o-C6H4{B(Ph)N(tBu)CH2}](45). The mechanism studies suggest that the heterolytic cleavage of a C-C bond is operative in these processes.更多还原