Synthetic studies toward potent cytotoxic agents amphidinolides G and H: Synthesis of the entire C15C26 moiety of the top half

Stereoselective total synthesis of rubrenolide and rubrynolide

“…9 Diastereoselective allylation of 10 under Evans' conditions 10 with sodium hexamethyldisilazide (NaHMDS) and allyl bromide in THF at À78°C provided the desired allylated product 7 in 65% yield as a single diastereomer. The diastereoselectivity in this reaction can be explained by selective electrophilic addition from the lower face, due to presence of a benzyl group in the auxiliary as well as a chiral center in the alkyl The reductive cleavage of the chiral auxiliary in compound 7 with LiBH 4 and methanol in ether at 0°C furnished the alcohol 11 in 86% yield.…”

First Stereoselective Total Synthesis and Biological Evaluation of Amphidinin B and Its Analogues

“…[13] The resulting acid was coupled with chiral (S)-oxazolidin-2-one using mixed anhydride conditions, to furnish 14 in 81 % yield over two steps. [14] Diastereoselective alkylation of the sodium-enolate of 14 with iodomethane, followed by reductive cleavage of the chiral auxiliary, afforded alcohol 15 as the only isomer in 69 % overall yield (Scheme 1). The resulting hydroxyl group was converted into its tert-butyldimethylsilyl (TBS) ether followed by dihydroxylation with a catalytic amount of OsO 4 and a stoichiometric amount of 4-methylmorpholine N-oxide (NMO).…”

Synthesis of the Northern Hemisphere of Amphidinolide H2

“…It could be demonstrated that on treatment with amphidinolide H the actin cytoskeleton was modified whereas the microtubules remained unchanged. 8 The remarkable biological activity and the interesting structural features have initiated considerable synthetic efforts, but although several syntheses of fragments of H-type amphidinolides and the structural related amphidinolides B and L have been published, [9][10][11][12][13][14]15 to our knowledge no total synthesis of these amphidinolides has been accomplished so far.…”