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New Approach for the Stereoselective Synthesis of (+)-epi-Cytoxazone

“…3 Although natural sources of compounds that contain the oxazolidin-2-one nucleus are very rare, 5 Kakeya et al 6 were able to isolate a novel compound belonging to this class, (4R,5R)-5-hydroxymethyl-4-p-methoxyphenyl-1,3-oxazolidin-2-one, ((−)-cytoxazone, Figure 1), from Streptomyces bacteria. Nakata and co-workers 7 and Mori and Seki 8 performed the first asymmetric total syntheses of (−)-cytoxazone and thus confirmed its absolute configuration.…”

Direct catalytic cross-coupling of alkenyllithium compounds

“…Interestingly, compound 2q is an intermediate in the synthesis of (–)-cytoxazone, a Novel Cytokine Modulator Isolated from Streptomyces sp. 23 …”

“…Interestingly, compound 2q is an intermediate in the synthesis of (À)-cytoxazone, a Novel Cytokine Modulator Isolated from Streptomyces sp. 23 We envisioned extension of this coupling to allenyllithium 24 compounds, providing a synthesis of substituted allenes. 25 Under the optimized reaction conditions the coupling between (3-methylbuta-1,2-dienyl)lithium, readily available by direct metallation of the corresponding allene, and both 4-methoxybromobenzene and 2-chloronaphthalene proceeded in good yields and high regioselectivity and with less than 5% of regioisomeric alkyne arising from 1,3-lithium shi of the organolithium reagent.…”

Determination of the Absolute Configuration at the Two Cyclopropane Moieties of Plakoside A, an Immunosuppressive Marine Galactosphingolipid

“…Scheme summarizes our synthesis of the authentic samples of 2a and 3a and their derivatization to 2b and 3b . The known alcohol (6 S ,7 R )‐ 5 4 was oxidized under Swern conditions, and the resulting aldehyde was further oxidized with sodium chlorite to give the acid, (6 S ,7 R )‐ 2a . Treatment of 2a with (1 S ,2 S )‐ or (1 R ,2 R )‐ 4 in the presence of 3‐(3‐dimethylaminopropyl)‐1‐ethylcarbodiimide hydrochloride (EDC) gave (6 S ,7 R ,1′ S ,2′ S )‐ or (6 S ,7 R ,1′ R ,2′ R )‐ 2b .…”

“…For the synthesis of acid (9 S ,10 R )‐ 3a with a side‐chain longer than that of 2a , the known iodide (6 S ,7 R )‐ 6 4 was homologated by treatment with the lithium salt of propargyl alcohol tetrahydropyranyl (THP) ether to furnish (9 S ,10 R )‐ 7a . The corresponding free alcohol (9 S ,7 R )‐ 7b was reduced with diimide, and the resulting saturated alcohol (9 S ,10 R )‐ 8 was oxidized to give the carboxylic acid (9 S ,10 R )‐ 3a .…”