| Project/Area Number |
02640479
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機・錯塩・放射化学
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| Research Institution | Hiroshima University |
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Principal Investigator |
NAKAZAWA Hiroshi Hiroshima Univ., Fac. Sci., Associate Prof., 理学部, 助教授 (00172297)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1991: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1990: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | P-C bond activation / Catalysis / alpha-Ketophosphonate / Decarbonylation / Metathesis / 脱カルボニル化反応 / 触媒反応 / Pd錯体 / Ni錯体 |
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| Research Abstract |
Various alpha-ketophosphonates, RC(O)P(O)(OR')_2, are catalytically decarbonylated to give phosphonates, RP(O)(OR')_2, on treatment with PdR_2L_2(R = Me, Et ; L = tertiary phosphine), Pd(PPh_3)_4, or Pd(PCy_3)_2. Crossover experiments of two kinds of alpha-ketophosphonates revealed that a metathesis reaction at a P-C bond of an alpha-ketophosphonate takes place prior to the decarbonylation in the presence of a catalytic amount of palladium complex(R^1C(O)P(O)(OR^2)_2 + R^3C(O)p(O)(OR^4)_2 <double arrow> R^1C(O)P(O)(OR^4)_2 + R^3C(O)P(O)(OR^2)_2. The reaction of trans-PdEt_2(PMe_3)_2 with RC(O)P(O)(OR')_2 for a several minutes in a toluene reflux condition affords transPd(PMe_3)_2(C(O)R)(P(O)(OR')_2) as yellow crystals. The isolated palladium complexes yield the corresponding phosphonate in toluene at the reflux temperature and also serve as a catalyst of the decarbonylation and metathesis reactions of alpha-ketophosphonates. The overall catalytic decarbonylation reaction is proposed to consist of oxidative addition of RC(O)P(O)(OR')_2 at a P-C bond to a "PdL_2" species generated from PdR_2L_2 or PdL_4 to give trans-PdL_2(C(O)R)(P(O)(OR')_2), followed by decarbonylation of the C(O)R ligand to give PdL_2R(P(O)(OR')_2) and the subsequent reductive elimination to give RP(O)(OR')_2 with regeneration of a "PdL_2" species. The mechanism of the alpha-ketophosphonate metathesis reaction is also discussed.
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