Application of Oxidative and Reductive Transformations in the Structure Determination of Marine Natural Products

Abstract

This review highlights the application of oxidative and reductive chemical transformations in the structure determination of complex marine natural products, including their absolute configurations. Workability of the Baeyer–Villiger reaction, ozonolysis, periodate oxidation, hydrogenolysis, and reductive amination, as well as other related chemical transformations, are discussed.

Koilodenoids A–G, immunosuppressive spiro dimers of diterpenoids from Koilodepas hainanense: structural elucidation and biomimetic transformation

“…The 40 carbon resonances in the 13 C NMR spectrum (Table 1, Fig. S11 in the ESI †) were classified using the HSQC spectrum into five carbonyl carbons (δ C 215.4, 215.2, 213.9, 206.2, and 173.8), four sp 3 methines, eighteen sp 3 methylenes (two oxygenated), one oxygen-bearing tertiary carbon (δ C 91.3), six sp 3 quaternary carbons, and six methyls.…”

“…of chemical transformations in the structural elucidation of complex natural products. [10][11][12][13][14] Biological assays revealed that compounds 1-7 showed moderate immunosuppressive effects against concanavalin A (ConA)-induced proliferation of T lymphocytes and lipopolysaccharide (LPS)-induced proliferation of B lymphocytes.…”

Oceanalin B, a Hybrid α,ω-Bifunctionalized Sphingoid Tetrahydroisoquinoline β-Glycoside from the Marine Sponge Oceanapia sp.

“…Peracetylation of a crude mixture containing 1 and rhizochalin (3) peracetates followed by separation using HPLC (YMC-Pack ODS-A column, EtOH-H 2 O, 80:20) gave mainly oceanalin B peracetate 1a. This peracetate was subjected to reductive ozonolysis (O 3 , then NaBH 4 ) followed by acetylation (Ac 2 O, pyridine) [12]. Two products were isolated by HPLC as a mixture and identified as peracetates 4 and 5, the same derivatives of oceanalin A [4] (Figure 2).…”

Streptocinnamides A and B, Depsipeptides from Streptomyces sp. KMM 9044

“…Ozonolysis without additional treatment to cleave the double bond in 1 supported the exact locations of the double bond and methoxy group. Ozonolysis was carried out in MeOH at −70 °C to yield the methyl ester of α-keto acid 5 , which was analyzed by (+)­HRMS/MS (ESI): [M + H] + calcd for [C 45 H 71 N 7 O 18 Cl] + m / z 1032.4539, found m / z 1032.4513 (Figure ).…”