Total Syntheses of Marine Natural Products Lyngbyabellin O and Lyngbyabellin P

Lyngbyabellins O and P are complex natural products derived from non-ribosomal peptide synthetase/polyketide synthase (NRPS/PKS) biosynthetic pathways and have been isolated from marine cyanobacterial sources. Both metabolites are characterized by the presence of two thiazole rings and a distinctive dichlorinated <i>β</i>-hydroxy acid side chain. Notably, lyngbyabellin P is further distinguished by the incorporation of a (3<i>R</i>,4<i>S</i>)-statine moiety. Herein, we report the first total syntheses of lyngbyabellins O and P, which are achieved through the convergent coupling of three key synthetic fragments, namely, two enantiomerically enriched thiazole subunits and a hydroxycarboxylic acid derivative, the latter constructed via a stereoselective aldol reaction. The total syntheses were completed in 12 and 13 longest linear steps (LLSs) for lyngbyabellins O and P, respectively, furnishing the natural products in overall yields of 5.6% and 2.5%.