Type II photooxygenation in polymer matrices for the synthesis of new antimalarial peroxides

Covalently immobilized porphyrins as photooxidation catalysts

“…Other recent and interesting proposals have appeared, such as immobilization of porphyrins in polymer microchannels, 12 linking fullerenes to amino functionalized silica gel, 13 benzophenone copolymer, 14 polymer spheresupported seco-porphyrazines, 15 porphyrins loaded in polystyrene beads, 16 porphyrin dendrimer structures, 17 and polystyrene nanocontainers doped with porphyrins. 18 …”

Diastereoselective schenck ene reaction of singlet oxygen with chiral allylic alcohols; access to enantiomerically enriched 1,2,4-trioxanes

“…[12][13][14] Given the promising profile of some of these endoperoxides we were interested in developing a general asymmetric route to 1,2,4-trioxanes in this class and here we wish to report the synthesis of spirocyclic 1,2,4-trioxanes 1-8 in high enantiomeric purities (Fig. 2).…”

“…Enantioselective addition of R 2 Zn reagent to 3-methyl-2-butenal catalysed by (þ)-MIB or (À)-MIB yielded both the enantiomers of the chiral allylic alcohols 9-11 (90-98% ee), which were subjected to diastereoselective photooxygenation in the presence of tetraphenylporphine (TPP) to obtain (R,R)-threo-or (S,S)-threo-b-hydroperoxy alcohols (12)(13)(14). Reaction of b-hydroperoxy alcohols (12-14) with different cyclic ketones produced optically active trioxanes 1-8.…”

Synthesis of (6S)-6-hydroxy-4-epi-shikimic acid

“…After 3 days of irradiation of 3 under solid state conditions using a polystyrene matrix as the reaction media, 15 a minor amount (20%) of the substrate had reacted with introduction of a hydroperoxy functionality at C-3. Upon standing, this compound converted rapidly to the 3-dehydro derivative and thus could not be used for our synthetic strategy.…”