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Synthesis and structural characterization of amido heteroscorpionate rare-earth metal complexes and hydroamination of aminoalkenesElectronic supplementary information (ESI) available: Experimental details, procedures for catalytic intramolecular hydroamination; kinetic measurements and representative kinetic plots. CCDC 1059154. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5nj00930h
The synthesis, characterization and fluxional behaviour of novel heteroscorpionate rare-earth (including the group 3 metals, scandium and yttrium) complexes are reported. The reaction of acetamide and thioacetamide heteroscorpionate protio-ligands pbptamH, tbptamH, pbpamH and ( S )-mbpamH with 1 equ...
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| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Online Access: | Get full text |
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| Summary: | The synthesis, characterization and fluxional behaviour of novel heteroscorpionate rare-earth (including the group 3 metals, scandium and yttrium) complexes are reported. The reaction of acetamide and thioacetamide heteroscorpionate protio-ligands pbptamH, tbptamH, pbpamH and (
S
)-mbpamH with 1 equivalent of tris(silylamide) precursors [M{N(SiHMe
2
)
2
}
3
(thf)
n
] (
n
= 1, M = Sc;
n
= 2, M = Y, Lu) proceeded to give good yields of neutral heteroscorpionate disilylamide complexes [M{N(SiHMe
2
)
2
}
2
(κ
3
-pbptam)(thf)
n
] (M = Sc,
n
= 0,
1
; M = Y,
n
= 1,
2
; M = Lu,
n
= 1,
3
), [M{N(SiHMe
2
)
2
}
2
(κ
3
-tbptam)(thf)
n
] (M = Sc,
n
= 0,
4
; M = Y,
n
= 1,
5
; M = Lu,
n
= 1,
6
), [M{N(SiHMe
2
)
2
}
2
(κ
3
-pbpam)(thf)
n
] (M = Sc,
n
= 0,
7
; M = Y,
n
= 1,
8
; M = Lu,
n
= 1,
9
) and [M{N(SiHMe
2
)
2
}
2
{κ
3
-(
S
)-mbpam}(thf)
n
] (M = Sc,
n
= 0,
10
; M = Y,
n
= 1,
11
; M = Lu,
n
= 1,
12
). Scandium complexes were isolated as THF-free compounds with a pseudo five-coordinate environment, while yttrium and lutetium complexes were isolated with an octahedral geometry due to the coordination of a THF molecule. The fluxionality of complexes
1-12
in solution was investigated by VT NMR spectroscopy. The structures of these compounds were determined by spectroscopic methods and the X-ray crystal structure of
1
was also established. Complexes
1-12
are efficient catalysts for the intramolecular hydroamination of aminoalkenes, with TOF values up to 198 h
−1
obtained at 70 °C for 2,2-diphenyl-pent-4-enylamine (
13
) using complex
11
as a catalyst. Enantioselectivities of up to 99% ee were achieved with the cyclization of aminoalkene
13
using the single enantiopure complex
12
. The hydroamination reactions showed a zero-order rate dependence on substrate concentration and first-order rate dependence on catalyst concentration.
New amide heteroscorpionate rare-earth complexes were developed and used as efficient catalysts for the intramolecular hydroamination of aminoalkenes. |
|---|---|
| ISSN: | 1144-0546 1369-9261 |
| DOI: | 10.1039/c5nj00930h |