Insight into the Selective Room-Temperature Platinum(II) Catalytic Hydration of Alkynes in Water
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- 作者：Derrick W. Lucey and Jim D. Atwood
- 刊名：Organometallics
- 出版年：2002
- 出版时间：June 10, 2002
- 年：2002
- 卷：21
- 期：12
- 页码：2481 - 2490
- 全文大小：122K
- 年卷期：v.21,no.12(June 10, 2002)
- ISSN：1520-6041
文摘
Three platinum complexes of water-soluble, bidentate phosphine ligands have beenprepared and characterized. The complexes, PtCl2(P-P) (P-P = (m-NaSO3C6H4)2PCH2CH2P(m-C6H4SO3Na)2, DPPETS, (m-NaSO3C6H4)2PCH2CH2CH2P(m-C6H4SO3Na)2, DPPPTS, (m-NaSO3C6H4)2PCH2CH2CH2CH2P(m-C6H4SO3Na)2, DPPBTS), catalyze the hydration of 3-pentyn-1-ol and 4-pentyn-1-ol. 2-Pentyn-1-ol is slowly polymerized, allowing characterization of theintermediate 
1-allenyl complexes. For PtCl2(DPPBTS) the 1-allenyl complex Pt(C(Et)CCH2)(X)(DPPBTS), where X is either OH-, OH2, or Cl-, is formed. However for PtCl2(DPPPTS)and PtCl2(DPPETS) the extent of formation of the coordinated complex is much less. Thestability of the coordinated Pt(1-allenyl)(X)(P-P) complexes shows a significant effect onchelate ring size, with DPPBTS > DPPPTS > DPPETS being the order of decreasing stability.Catalytic hydrations of 4-pentyn-1-ol with PtCl2(P-P) show a major effect of chelate ringsize in the opposite direction, DPPETS > DPPPTS > DPPBTS. For 3-pentyn-1-ol catalytichydration is less affected by the chelate ring size. The effect of excess Cl- is also examined.A mechanism is proposed for the catalytic hydration involving coordination, cyclic attack bythe alcohol according to Baldwin's rules, and rearrangement to 5-hydroxypentan-2-one.
1-allenyl complexes. For PtCl2(DPPBTS) the 1-allenyl complex Pt(C(Et)CCH2)(X)(DPPBTS), where X is either OH-, OH2, or Cl-, is formed. However for PtCl2(DPPPTS)and PtCl2(DPPETS) the extent of formation of the coordinated complex is much less. Thestability of the coordinated Pt(1-allenyl)(X)(P-P) complexes shows a significant effect onchelate ring size, with DPPBTS > DPPPTS > DPPETS being the order of decreasing stability.Catalytic hydrations of 4-pentyn-1-ol with PtCl2(P-P) show a major effect of chelate ringsize in the opposite direction, DPPETS > DPPPTS > DPPBTS. For 3-pentyn-1-ol catalytichydration is less affected by the chelate ring size. The effect of excess Cl- is also examined.A mechanism is proposed for the catalytic hydration involving coordination, cyclic attack bythe alcohol according to Baldwin's rules, and rearrangement to 5-hydroxypentan-2-one.