Synthetic studies toward the disorazoles: synthesis of a masked northern half of disorazole D1 and a cyclopropane analog of the masked northern half of disorazole A1

Hypervalent Iodine Reagents for the Oxidation of Alcohols and Their Application to Complex Molecule Synthesis

“…(33). [60] 33 REVIEWS Hirofumi Tohma, Yasuyuki Kita Combination of DMP oxidation and olefination without isolation of epimerization-prone or unstable aldehydes and ketones can be used widely in total syntheses of various natural products. For instance, oxidation of 45 with 2 cleanly produced ketone 46.…”

Isolation, biology and chemistry of the disorazoles: new anti-cancer macrodiolides

“…Previous work by Meyers29,33 and Hoffmann36,40,41 revealed important synthetic parameters, including the instability of the triene backbone and the significance of the position of the alkyne which served both to mask the ( Z )-olefin(s) of the triene unit as well as facilitate the macrolactonization. Wipf and Graham were able to capitalize on these important findings and devise a synthetic approach that utilized a Sonogashira coupling to construct the carbon–carbon bonds at C-8/C-9 of the dienyne monomer 66 (Fig.…”

“…Swern oxidation of the primary alcohol proceeded smoothly, but, unfortunately the subsequent alkyne addition using 1-lithiopropyne proved problematic, resulting in formation of a 1.1: 1.0 ( syn: anti ) ratio of separable diastereomers at C-16. Hoffmann also reported difficulties in the selective formation of the neopentyl anti -1,3-diol 36,41,46. Attempts at improving the diastereoselectivity for the generation of this diol segment have thus far proved unsuccessful.…”

“…41,49 Asymmetric Charette cyclopropanation of mono-PMB protected cis-butene diol 99 followed by Dess–Martin oxidation afforded aldehyde 100 . Subsequent Takai olefination of aldehyde 100 provided vinyl iodide 101 in a moderate 49% yield.…”

Total Synthesis of (−)‐Amphidinolide E

“…[4] Suzuki coupling [5] of 3 with the known vinyl iodide 4 [6] proceeded smoothly, and the resulting diene was transformed into aldehyde 5 by removal of the TBS protecting group and oxidation (Scheme 2). The known diol 6 [7] served as the starting material in the synthesis of fragment C. DDQ oxidation of 6 provided the corresponding PMP cyclic acetal, which was converted into aldehyde 7 by MOM protection of the remaining hydroxy group and reduction with DIBAL.…”