Two-coordinate group 14 element(II) hydrides as reagents for the facile, and sometimes reversible, hydrogermylation/hydrostannylation of unactivated alkenes and alkynes
Two-coordinate group 14 element(II) hydrides as reagents for the facile, and sometimes reversible, hydrogermylation/hydrostannylation of unactivated alkenes and alkynes
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DOI：
10.1039/c5sc03376d
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发表时间：
2015-01-01
期刊：
影响因子：
8.4
通讯作者：
Jones, Cameron
中科院分区：
文献类型：
--
作者：
Hadlington, Terrance J.;Hermann, Markus;Jones, Cameron
溶液中稳定的二配位氢化四丙烯：E(H)(L-匕首)(E=Ge或Sn；L-匕首=-N(Ar-匕首)(SiPr3i)；Ar-匕首=C6H2{C(H)Ph-2}(2)Pr-I-2，6，4)，与各种未活化的环烯和非环烯以及一种内烯的反应，导致不饱和基质在常温下特定区域的快速湿法金属化反应。这些反应的产物[L-匕首E(C2H4R)](E=Ge或Sn，R=H，Ph或Bu-t)，[(LE)-E-匕首{CH(CH2)(3)(CH2)(N)}](E=Ge，n=1，2或3；E=Snn，n=1)和[(LE)-E-匕首{C(Ph)]=C(H)(Me)}]，包括第一个结构表征的双配位氨基/烷基锗和锡烯。环烯烃水合反应在环境条件下是完全可逆的，计算和实验van‘t Hoff分析表明，该过程是通过从金属配位的环烷基配体上消除β-氢化物进行的。类似地，Ge(H)(L匕首)与1，5-环辛二烯和2-甲基-2-丁烯的反应都可能通过β-氢化物消除过程进行，导致所涉及的烯烃干净的异构化，以及随后的加氢胚芽基化，分别得到[(LGe)-Ge-匕首(2-环辛烯基)]和[(LGe)-Ge-匕首{C2H4C(H)Me-2}]。[(LGe)-Ge-dagger(C5H9)]和[(LGe)-Ge-dagger(C5H9)]与质子化试剂HCl、NH3和EtH反应，导致Ge(II)中心的氧化加成，形成稳定的手性Ge(IV)络合物[(LGe)-Ge-dagger(C5H9)(H)Cl]和[(LGe)-Ge-dagger(Et)(H)R](R=NH2或OEt)。相反，[(LSnEt)-锡-匕首]与(BuOH)-O-t或TEMPOH(TEMP=2，2，6，6-四甲基哌啶)之间的相关反应通过乙烷消除进行，得到锡(II)产物[(LSNR)-锡-匕首](R=OBut或OTEMP)。此外，[(LGe)-Ge-匕首(C6H11)]和[(Lsn)-Sn-匕首(C2H4But)]在O-2作用下分别生成了氧桥联金属(IV)二聚体[{L-匕首(C6H11)Ge(m-O)}(2)]和[{L-匕首(BuC2H4)-C-t)Sn(m-O)}(2)]。
Reactions of the solution stable, two-coordinate hydrido-tetrylenes, : E(H)(L-dagger) (E = Ge or Sn; L-dagger = -N(Ar-dagger)(SiPr3i); Ar-dagger = C6H2{C(H)Ph-2}(2)Pr-i-2,6,4), with a variety of unactivated cyclic and acyclic alkenes, and one internal alkyne, lead to the rapid and regiospecific hydrometallation of the unsaturated substrate at ambient temperature. The products of the reactions, [L-dagger E(C2H4R)] (E = Ge or Sn, R = H, Ph or Bu-t), [(LE)-E-dagger{CH(CH2)(3)(CH2)(n)}] (E = Ge, n = 1, 2 or 3; E = Sn, n = 1) and [(LE)-E-dagger{C(Ph)]=C(H)(Me)}], include the first structurally characterised examples of two-coordinate amido/alkyl germylenes and stannylenes. The cycloalkene hydrometallation reactions are cleanly reversible under ambient conditions, a process which computational and experimental van't Hoff analyses suggest proceeds via beta-hydride elimination from the metal coordinated cycloalkyl ligand. Similarly, the reactions of : Ge(H)(L-dagger) with 1,5-cyclooctadiene and 2-methyl-2-butene, both likely proceed via beta-hydride elimination processes, leading to the clean isomerisation of the alkene involved, and its subsequent hydrogermylation, to give [(LGe)-Ge-dagger(2-cyclooctenyl)] and [(LGe)-Ge-dagger{C2H4C(H)Me-2}], respectively. Reactions of [(LGeEt)-Ge-dagger] and [(LGe)-Ge-dagger(C5H9)] with the protic reagents, HCl, NH3 and EtOH, lead to oxidative addition to the germanium(II) centre, and formation of the stable chiral germanium(IV) complexes, [(LGe)-Ge-dagger(C5H9)(H) Cl] and [(LGe)-Ge-dagger(Et)(H)R] (R = NH2 or OEt). In contrast, related reactions between [(LSnEt)-Sn-dagger] and (BuOH)-O-t or TEMPOH (TEMP = 2,2,6,6-tetramethylpiperidinyl) proceed via ethane elimination, affording the tin(II) products, [(LSnR)-Sn-dagger] (R = OBut or OTEMP). In addition, the oxidation of [(LGe)-Ge-dagger(C6H11)] and [(LSn)-Sn-dagger(C2H4But)] with O-2 yields the oxo-bridged metal(IV) dimers, [{L-dagger(C6H11) Ge(m-O)}(2)] and [{L-dagger((BuC2H4)-C-t) Sn(m-O)}(2)], respectively.