Abstract
The use of a bifunctional non-cross-linked polystyrene bearing
both phosphine and phenol groups for the organocatalytic isomerization
of alkynes bearing electron-withdrawing ester substituents to afford
the corresponding (E ,E )-dienes
in excellent yield and stereoselectivity is described. When polystyrene
functionalized with only phosphine groups was used as the catalyst,
either low or no yield of the desired product was obtained. Thus
both of the functional groups of the bifunctional polystyrene catalyst
were essential for efficient catalysis to occur. This bifunctional
polymeric catalyst was also used to synthesize (E ,E ,E )-trienes
and (E ,E )-diene-substituted
2(H )-pyran-2-ones from the corresponding
alkynes.
Key words
organocatalysis - polymer-supported catalyst - alkyne isomerization - dienes - triphenylphosphine - phenol
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