First Total Synthesis of (±)-Flustraminol B

Marine natural products

“…731 Total synthesis of the alkaloid flustraminol B, from the marine bryozoan Flustra foliacea, 736 has been reported. 737 Desformylflustrabromine 738 and desformylflustrabromine-B, 739 metabolites of Flustra foliacea, were synthesised as hydrochloride salts. 740 Tambjamines C, 741 E-F 742 and G-J, 743 from Sessibugula translucens and the nudibranch predators, 741,744 were synthesised, as was a related yellow pigment isolated from the marine bacterium Pseudoalteromonas tunicata.…”

Syntheses of three naturally occurring polybrominated 3,3′-bi-1H-indoles

“…For example, 2,6-dibromination of 3-cyanomethylindole using NBS-SiO 2 in dichloromethane gave 2,6-dibromo-3-cyanomethylindole (81%), 2,5-dibromo-3-cyanomethylindole (3%), and 2,4-dibromo-3-cyanomethylindole (5%). 17 3-Methylindole afforded selectively 2,6-dibromo-3-methylindole using NBS-SiO 2 in dichloromethane 18 and 3-phenylindole using NBS in acetic acid furnished a 6:1 ratio of 2,6-dibromo-3-phenylindole and 2,5-dibromo-3-phenylindole. 19 In contrast, a 3:4 ratio of 2,6:2,5-dibromination was observed from brominations of methyltryptophan employing NBS in AcOH/HCOOH.…”

Studies toward the Synthesis of Chartelline C

“…To a mixture of imidazole segment 9 (10.3 g, 19.1 mmol), indole segment 10 , (22.7 g, 0.0517 mmol), CuI (727 mg, 3.82 mmol), PPh 3 (1.99 g, 7.59 mmol), and Pd 2 (dba) 3 ·CHCl 3 (2.0 g, 1.9 mmol) were added dry benzene (500 mL) and dry n -BuNH 2 (7.6 mL, 0.077 mol) at room temperature under an Ar atmosphere. The resulting mixture was degassed by three freeze–thaw cycles, and the flask was filled with Ar.…”

“…Macrolactamization of amino acid D followed by dehydration and C3-bromination would afford bromoenamide B′ , which is a similar intermediate in the Baran’s synthesis of 1 . Amino acid D would be synthesized by the Sonogashira coupling of the known indole segment E , with imidazole segment F .…”