Evolution of a Strategy for Total Synthesis of the Marine Fungal Alkaloid (±)-Communesin F

Abstract

A new synthetic strategy for construction of the heptacyclic marine fungal alkaloid (±)-communesin F has been devised. Key reactions include an intramolecular Heck cyclization of a tetrasubstituted alkene to generate a tetracyclic enamide bearing one of the quaternary carbon centers (C7) of the alkaloid, an intramolecular reductive cyclization of an N-Boc aniline onto the oxindole moiety to form a pentacyclic framework containing the southern aminal, a stereoselective N-Boc-lactam enolate C-allylation to introduce the second quaternary carbon center (C8), and an azide reduction/N-Boc-lactam-opening cascade leading to the northern aminal.

Molecular diversity of spirooxindoles. Synthesis and biological activity

“…The synthetic strategies for the formation of the spiro [indoline-3,4 -piperidine] skeleton are based on a large variety of classical synthetic methods [161,162]. Thus, an intramolecular Heck reaction of a tetrasubstituted alkene 271 Fig.…”

Elucidation of the Concise Biosynthetic Pathway of the Communesin Indole Alkaloids

“…Because of their remarkable structures, the communesins have inspired numerous synthetic studies,3 including completed or formal total syntheses by the groups of Qin,3a,b Ma,3c,d Weinreb,3e,f Funk,3g,h and Stoltz 3i–k. In contrast, the biosynthetic pathway of the communesins has remained unexplored since their isolation except for preliminary feeding experiments, which showed that the communesin core is assembled from two indole precursors derived from tryptophan 2e.…”

Asymmetric Total Syntheses of Communesin F and a Putative Member of the Communesin Family

“…Treatment of aldehyde 16 with alkynyl Grignard reagent 17 furnished alkynyl alcohol 18 , which underwent a facile Au‐catalyzed Meyer–Schuster rearrangement to afford enone 19 and further converted to tertiary alcohol 20 through the action of MeLi. Similar to the reported reaction sequence,– intramolecular cyclization of 20 upon treatment with PPTS furnished hexacyclic intermediate 21 uneventfully. Finally, imidate formation (Meerwein salt, BF 4 ⋅OEt 3 ) of pyrrolidinone 21 followed by a chemoselective Boc‐carbamate removal provided heptacyclic imine 22 , our targeted common precursor and potentially applicable to a number of communesins shown in Figure .…”