- Isomerisation of ω-hydroxyalkenes under hydroxycarbonylation conditions in palladium catalysed aqueous phase systems
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The ω-hydroxyolefins 3-buten-1-ol, 3-buten-1-methyl-1-ol and 4-penten-1-ol were subjected to hydroxycarbonylation conditions in water in the presence of PdCl2(PhCN)2 and 4-8 equiv. of water soluble tris(3-sodiumsulfonatophenyl)phosphine (TPPTS), or N-bis(N′,N′-diethyl-2-aminoethyl)-4-aminomethylphenyl-diphenylphosphine (N3P). Under conditions of high conversion, the olefins primarily undergo isomerisation through a chain walking mechanism with selectivities for aldehyde ranging from 65% to 98%, with the lower values for longer chain alcohols. The lactones formed as the minor product are almost exclusively branched, indicating that in the first step 2,1-insertion is strongly favoured over 1,2-insertion. In the N3P system also linear lactone is produced at lower conversion. Running the reaction in D2O produces multiple deuterium incorporation in all positions of the carbon chain. A mechanism is discussed.
- Ionescu, Adriana,Ruppel, Markus,Wendt, Ola F.
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p. 3806 - 3815
(2007/10/03)
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- A Novel Cleavage of Five-Membered Cyclic Acetals Using Sodium Hydrogen Telluride
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Under mild conditions, a variety of 1,3-dioxolanes are easily cleaved in high yields by treatment with sodium hydrogen telluride in ethanol.
- Lue, Ping,Fan, Wei-Qiang,Zhou, Xun-Jun
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p. 692 - 693
(2007/10/02)
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