LONG-RANGE GOAL:

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LONG-RANGE GOAL Selective amination of CH-bonds
in Cu nitrene systems
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SYSTEMS FOR DIRECT HYDROCARBON AMIDATION

• PhINTs / Mn porphyrinate
• PhINTs / Rh2(OAc)4
• ButOOCONHTs / Cu(OTf)2
• TsNCl(Na) / Cu(II)

Ru(salen)(PPh3)2 Ru(Tp)(PPh3)2Cl RuCl2(cod)n RuCl3x H2O Reaction condition 1.1 equ of substrate, r.t. 3 h 2 mol of catalyst
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SUBSTRATE / AMIDATION SELECTIVITY
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IN SITU PREPARATION of PhINTs ?
PhI(OAc)2 H2NR ? PhINR 2 AcOH
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OTHER AMIDES H2NR AS A SOURCE OF NHR ?
H2NSO2Me ? PhINSO2Me ? H2NCOPh ?
PhINCOPh ?
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SOME MECHANISTIC ASPECTS

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SOME MECHANISTIC ASPECTS
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SOME MECHANISTIC ASPECTS

Mechanism, postulated for Mn-porphyrin systems
Ru(N-N)2Cl2 PhINTs ?
Ru(N-N)2(NTs)Cl ES-MS, m/z 756
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JACS Communications 2003, 125, 12078-12079
Cyclohexane and Benzene Amination by Catalytic
Nitrene Insertion into C-H Bonds with the
Copper-Homoscorpionate Catalyst TpBr3Cu(NCMe) M.
Mar Diaz-Requejo, Tomas R. Belderrain, M. Carmen
Nicasio, Swiatoslaw Trofimenko, Pedro J. Perez
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SIMPLE Cu CATALYSTS FOR CH AMINATION
OUR FINDINGS 1) Alkane amination AND
dehydrogenation/aziridination
2) Alkylarene amination AND amine
dehydrogenation
3) Simple CuII complexes are efficient catalysts
of these reactions
Activity of catalysts increases in the presence
of NaBArF4
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EXAMPLE OF OLEFIN AZIRIDINATION
Table 1. Results of olefin aziridination with 1
equivalent of PhINTs in the presence of 5 mol
of (L)CuCl2 and no or 2 equivalents of NaBArF4
in CHCl3 at 296 K
Entry Substrate Yield of aziridine, on olefin (time, min) Yield of aziridine, on olefin (time, min) Yield of aziridine, on olefin (time, min) Yield of aziridine, on olefin (time, min) Yield of aziridine, on olefin (time, min) Yield of aziridine, on olefin (time, min)
Entry Substrate dpm dpp Cl-dpm Me-dpm (py)2 dipy
2 equivalents of NaBArF4 per (L)CuCl2 2 equivalents of NaBArF4 per (L)CuCl2 2 equivalents of NaBArF4 per (L)CuCl2 2 equivalents of NaBArF4 per (L)CuCl2 2 equivalents of NaBArF4 per (L)CuCl2 2 equivalents of NaBArF4 per (L)CuCl2
1 cis-Cyclooctene 66 (1) 82 (1) 83 (1) 67 (5) 83 (1) 73 (10)
2 Styrene 95 (1) 95 (1) 98 (1) 93 (2) 97 (10) a 98 (5)
3 Tetramethylethylene 76 (5) 81 (5) 91 (2) 75 (1) 94 (2) 50 (5)
4 tert-Butylethylene 49 (10) 60 (3) 63 (5) 31 (40) 55 (3)
5 Methyl acrylate 35 (30) 45 (30) 45 (20) 38 (25) 44 (5)
No NaBArF4 No NaBArF4 No NaBArF4 No NaBArF4 No NaBArF4 No NaBArF4
6 Styrene 97 (20) 81 (5) 65 (20) 92 (5)
7 Tetramethylethylene 51 (30) 67 (2) 55 (30) 89 (2)
8 cis-Cyclooctene 50 (15) 57 (1) 36 (60) 71 (2)
9 tert-Butylethylene 21 (30) 19 (15) 31 (15)
a 1 mol of catalyst

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PLAUSIBLE MECHANISM OF CH AMINATION

• Facts in support of the scheme above
• Addition of PhINTs to CuII complex causes its
  color change from blue to yellow (CuIII?). The
  yellow color is gone when PhINTs reacted
  completely.
• Additional hypotheses
• 1) Dinuclear Cu complexes are responsible for
  alkane and amine dehydrogenation
• 2) Efficiency of Cu catalyst is a function of the
  ability of L to withstand oxidative degradation
• 3) Part of PhINTs forms less active nitrene
  dimers TsNNTs

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QUESTIONS / PLANS FOR FUTURE

• Are the reaction products, N-tosylamides /
  aziridines, - good or bad ligands for CuII
  based catalysis of nitrene transfer?
• What is the catalyst resting state?
• If they are poor ligands, how to modify pyridine
  ligands to achieve a better performance to cost
  ratio?
• Is it possible to detect spectroscopically (NMR,
  UV-Vis etc) plausible CuIII - nitrene adducts?
• Is it possible to prepare such robust ligands
  which will allow isolation of Cu-nitrene adducts?
• Will dinuclear-only Cu-complexes be more
  efficient in catalytic dehydrogenation?
• Is it possible to use TsNNTs as a source of
  NTs?
• How reactivity of Cu-nitrene adducts will be
  influenced by the nature of R group in nitrenes
  RN? Is it possible to enhance their reactivity so
  that methane CH bonds can be attacked? Or tune
  their reactivity so that only selective CH bond
  cleavage will occur (3o-only, e.g.)?