posted on 2024-02-15, 15:07authored bySandra Rico-Martínez, Adrián Ruiz, Beatriz López-Iglesias, Cristina Álvarez, Ángel E. Lozano, Jesús A. Miguel
Two microporous polymer networks having a confined AuI carbene catalyst were obtained and tested for the skeletal
rearrangement
of enynes. These catalysts were obtained from precursor porous organic
polymers (POPs), a type of microporous polymer network, synthesized
by the reaction of isatin or a mixture of isatin/trifluoroacetophenone
(1:1) with triptycene (POP1 and POP2, respectively)
through an electrophilic aromatic substitution, EAS, reaction promoted
by trifluoromethanesulfonic acid. These precursors could be easily
functionalized through the lactam moiety to form AuI carbene
catalysts (POP1-AuCarbene and POP2-AuCarbene). The confined carbenes proved to be very active for the skeletal
rearrangement of dimethyl 2-(3-methyl-2-butenyl)-2-propinylmalonate
enyne. A large increase in the stability of the AuI catalysts
was observed compared to those of most of the homogeneous catalysts
described so far in the bibliography. This long-term stability was
associated with the separation of AuI atoms, induced by
their confinement in the microporous networks. In particular, POP2-AuCarbene exhibited outstanding long-term stability,
maintaining catalytic activity even after several months.