Toward Permetalated Alkyne/Azide 3 + 2 or “Click” Cycloadducts
摘要:
The Cu(I)-catalyzed reaction of the platinum butadiynyl complex trans-(C6F5)(p-tol(3)P)(2)Pt(C C)(2)H and rhenium cyclopentadienylazide complex (eta(5)-C5H4N3)Re(CO)(3) yields the 1,2,3-triazole trans-(C6F5)(p-tol(3)P)(2)PtC CC CHN(eta(5)-C5H4)Re(CO)(3))N N (54%), which upon treatment with Re-(CO)(5)OTf or Re(CO)(5)Br affords Re(CO)(5)+TfO- or cis-Re-(CO)(4)Br adducts derived from attack at N(3) (84-98%). The crystal structures of solvates of these three complexes are compared, but attempts to metalate the =CH groups were unsuccessful. However, the reaction of monometallic trans(C6F5)(p-tol(3)P)(2)PtC CC CHN(CH2C6H5)N=N and Mel gives an N(3)-methyl triazolium salt (81%), which upon addition of Ag2O and [RhCl(cod)](2) yields the N-heterocyclic carbene complex trans-(C6F5)(p-tol(3)P)(2)PtC CC-C(RhCl(cod))-N(CH2C6H5)-N-N(Me). Further experiments and analyses suggest that =CH derivatization is possible only when the H-1 NMR chemical shift is downfield of ca. delta 7.9 ppm. Electropositive metal fragments generally effect upfield shifts, meaning that insulating spacers, electronegative ligands, and/or new chemical methodologies will be required to construct tetrametallic arrays via click chemistry.
“Click” Chemistry in Metal Coordination Spheres: Copper(I)-Catalyzed 3+2 Cycloadditions of Benzyl Azide and Platinum Polyynyl Complexes <i>trans</i>-(C<sub>6</sub>F<sub>5</sub>)(<i>p</i>-tol<sub>3</sub>P)<sub>2</sub>Pt(C≡C)<sub><i>n</i></sub>H (<i>n</i> = 2−6)
作者:Sébastien Gauthier、Nancy Weisbach、Nattamai Bhuvanesh、John A. Gladysz
DOI:10.1021/om900680q
日期:2009.10.12
Benzyl azide and the terminal polyynyl complexes trans-(C6F5)(p-tol(3)P)(2)Pt(C C)(n)H (n = 2-6) undergo 3+2 "click" cycloadditions in the presence of CuSO4/ascorbic acid to give the 1,2,3-triazoles trans-(C6F5)(p-tol(3)P)(2)Pt(C C)n-Gamma C=CHN(CH2C6H5)N=N, four of of which are structurally characterized..