Stereoselective total synthesis of synparvolide B and epi-synparvolide A

Are Alkyne Reductions Chemo-, Regio-, and Stereoselective Enough To Provide Pure (Z)-Olefins in Polyfunctionalized Bioactive Molecules?

“…This catalyst is usually employed in aromatic solvents (pyridine, benzene, toluene) ,− or polar protic solvents (MeOH, EtOH). , Several groups, such as protected ,, and free , alcohols, epoxides, and heteroazines, are tolerated.…”

“…In addition, attention must be paid, since in the literature the ‘Lindlar’ term is confusing. Effectively, in some cases in the discussion section it is written “Lindlar” while the experimental part described a Pd/BaSO 4 ,− or Pd/CaSO 4 reagent or the contrary. , …”

Applications of Wittig Reaction in the Total Synthesis of Natural Macrolides

“…[69] The formation of decarestrictine D 23 was started from market purchasable (+)-diethyl L-tartrate that after several steps afforded benzyl ether 19 in 73% yield. The latter using Swern oxidation [70] and Wittig homologation with methoxymethyltriphenylphosphonium chloride and lithium hexamethyldisilazide in dry tetrahydrofuran afforded the corresponding enol ether that upon hydrolysis with mercury(II) acetate and subsequent by an in situ reduction with sodium borohydride in tetrahydrofuran/H 2 O (1 : 1.2) gave homologated alcohol 20. [71][72][73][74] The latter after several steps gave decarestrictine O 14 (Scheme 5).…”

Stereoselective synthesis of (−)-synparvolide B

“…The crude product was purified by column chromatography (eluent: PE-EtOAc, 7:3) to afford the corresponding acrylic ester 4 (0.35 g, 85%) as a colorless oil; A solution of Grubbs' first-generation catalyst G-I (0.069 g, 0.084 mmol, 10 mol %) in CH 2 Cl 2 (20 ml) was added dropwise to a solution of 4 (0.30 g, 0.847 mmol) in CH 2 Cl 2 (30 mL) at rt, and stirring was continued for 15 h at reflux. The solvent was evaporated and the crude product purified by silica gel column chroma-2929, 1731,1425, 1377, 1237, 1034, 950, 759, 817 cm À1 ; 1 H NMR (CDCl 3 , 300 MHz): d 6.90 (ddd, J = 9.6, 5.4, 4.1 Hz, 1H), 6.05 (ddd, J = 9.8, 1.8, 1.5 Hz, 1H), 5.69-5.57 (m, 2H), 5.39 (ddd, J = 8.8, 6.6, 2.0 Hz, 1H), 5.14-5.06 (m, 1H), 5 …”