Synthesis and Configuration of Neomaclafungin A

Abstract

The relative and absolute configuration of neomaclafungins were impossible to establish by spectroscopic analyses alone because of the lack of exploitable H- H couplings and nOes between the upper and the lower subunits. This very difficult task now is finally completed by an enantioselective total synthesis of neomaclafungin A (revised) and its diastereomer (reported). The results also provided a key reference for the complete structures for other neomaclafungins and the long-known closely related natural product maclafungin.

Marine natural products

“…New compounds from the Firmicutes genera Bacillus, Geobacillus and Thermoactinomyces include 201-216, [98][99][100][101][102][103][104][105][106] while new NPs from the Proteobacteria genera Pseudoalteromonas, Pseudomonas, Pseudovibrio, Vibrio, Thalassiosira, Enhygromyxa and Labrenzia include 217-241. [107][108][109][110][111][112][113][114][115][116] Closer inspection of the spectroscopic and spectrometric data (or lack thereof) presented in several articles reporting new marine bacteria NPs, suggest that the structure assignment of several compounds (202-205, 99 The rst total syntheses of the marine-derived bacteria compounds neomaclafungin A 242, 117 usabamycins A and C, 118 (À)-marinisporolide C, 119 seoaracenes A and B, 120 actinoranone 243, 121 enhygrolide A, 122 discoipyrroles C and D, 123,124 and metagenetriindole A 125 has been achieved.…”

“…The enantioselective total synthesis of neomaclafungin A 242 resulted in the relative and absolute congurations of this potent antifungal agent being revised. 117 These data should, in the future, assist in the complete structures of other neomaclafungins and the closely related metabolite, maclafungin being revised.…”