Stereochemistry of palytoxin. Part 3. C7-C51 segment

Mitomycins syntheses: a recent update

“…However, three equivalents of osmium tetroxide and one week of reaction time were needed to get decent yield of the diasteromeric diols 164 and 165 from olefin 163 ( Scheme 46 ). This is probably due to the poor reactivity of the olefin, which is considerably reduced by the inductive effects of the neighbouring ketal and acetate groups [ 120 – 121 ]. The diol 164 was isolated by chromatography and selectively mesylated on hydroxyl 2.…”

Palytoxins: A still haunting Hawaiian curse

“…1) Ko et al 1982;Fujioka et al 1982;Cha et al 1982;Moore et al 1982). Palytoxin stereochemistry, encompassing 64 stereogenic centers along with eight double bonds, was confirmed a few years later by synthetic studies (Armstrong et al 1989).…”

Addition Reactions with Formation of Carbon–Oxygen Bonds: (iii) Glycol Forming Reactions

“…The hydroxylation of an alkene may be achieved by treatment with a suitable peroxycarboxylic acid, RC03H, the reaction proceeding (Scheme 4) by initial syn addition to give an epoxide (oxirane) (40), which undergoes acid-catalyzed ring scission in an anti manner through attack by the corresponding carboxylic acid, RC02H, normally present in the reaction medium, to give the monoesters (41) and (42). Hydrolysis of the ester mixture then affords a racemic mixture of the enantiomeric diols (43a) and (43b) with stereochemistry resulting from overall anti addition to the alkene.…”