Asymmetric total synthesis of 5′-epi-cochliomycin C

Crystal structure of C10H10O4

C10H10O4, monoclinic, P21/c (no. 14), a = 9.464(6) Å, b = 10.302(7) Å, c = 10.589(7) Å, β = 114.174(11)°, V = 941.8(10) Å3, Z = 4, R gt (F) = 0.0453, wR ref(F 2) = 0.1394, T = 173 K.

Asymmetric total syntheses of naturally occurring α,β-enone-containing RALs, L-783290 and L-783277 through intramolecular base-mediated macrolactonization reaction

Asymmetric total synthesis of two naturally occurring α,β-enone containing RALs, L-783290 and L-783277 is described in this article. An E-selective Horner-Wadsworth-Emmons (HWE) olefination was used as a key reaction to construct the C7'-C8' olefinic unsaturation in L-783290. An enantiopure alkyne addition to the aldehyde followed by Z-selective partial reduction was employed to construct the C7'-C8' olefinic unsaturation in L-783277. Biomimetic lactonization reaction was used to construct the macrolactone core in both the target molecules.

Resorcylic acid lactones (RALs) and their structural congeners: recent advances in their biosynthesis, chemical synthesis and biology

Resorcylic acid lactones (RALs) are naturally occurring 14-membered macrolactones that constitute a class of polyketides derived from fungal metabolites and that possess significant and promising biological activity.

Total Syntheses of the Resorcylic Acid Lactones Paecilomycin F and Cochliomycin C Using an Intramolecular Loh-Type α-Allylation Reaction for Macrolide Formation

Subjection of the resorcylic ester 16 to a Nozaki-Hiyama-Kishi reaction afforded the 12-membered lactone 17, while treatment of it under the Loh-type α-allylation conditions using indium metal gave the isomeric, 14-membered macrolide 18. Compound 18 was readily elaborated to the resorcylic acid lactone type natural products paecilomycin F and cochliomycin C.

Modular total syntheses of the marine-derived resorcylic Acid lactones cochliomycins a and B using a late-stage nozaki-hiyama-kishi macrocyclization reaction

The natural products cochliomycin A (1) and cochliomycin B (2), two resorcylic acid lactones obtained from marine sources, have been prepared in a concise and stereocontrolled manner from the readily accessible building blocks 4-6. Olefin cross-metathesis, trans-esterification and Nozaki-Hiyama-Kishi (NHK) macrocyclization reactions were employed in the key steps. Hydrolysis of the immediate precursor to cochliomycin B affords the resorcylic acid lactone zeaenol (24).

Asymmetric total synthesis of paecilomycin E, 10'-epi-paecilomycin E and 6'-epi-cochliomycin C

The asymmetric total syntheses of naturally occurring resorcylic acid lactone paecilomycin E and two of its structural congeners have been reported in this article. The major highlight of the synthetic venture is the application of the late stage Mitsunobu macrolactonization method (as it is difficult to achieve the desired products through the standard carboxyl activation method) of a properly functionalized seco-acid. The macrolactonization precursor was synthesized by applying an "E"-selective Julia-Kocienski olefination of a highly functionalized aromatic aldehyde and a sulphone, which constitutes all the stereocenters (C4', C5', C6' and C10'; 3S,7R,8R,9S) in the target molecule.