An Enantioselective Total Synthesis and Stereochemical Revision of (+)-Citrinadin B

Abstract

This manuscript describes an enantioselective synthesis of the naturally occurring alkaloid citrinadin B. The synthetic effort revealed an anomaly in the original structural assignment that has led to the proposal of a stereochemical revision. This revision is consistent with the structures previously reported for a closely related family of alkaloids, PF1270A-C. The synthesis is convergent and employs a stereoselective intermolecular nitrone cyloaddition reaction as a key step.

Molecular diversity of spirooxindoles. Synthesis and biological activity

“…The chirality at this center served as a control point when introducing other stereocenters in the pentacyclic core (Scheme 101). Citrinadin A has shown to exhibit cytotoxicity against murine leukemia L1210 (IC 50 6.2 mg/mL) and human epidermoid carcinoma KB cells (IC 50 10mg/mL) [199,200].…”

Simple indole alkaloids and those with a nonrearranged monoterpenoid unit

“…This was transformed to (À)-138, which led to the revision of the originally proposed stereochemical assignment (Scheme 40). 72 The welwitindolinone, possessing a bicyclo[4.3.1]decane ring system, is a unique family of oxyindole-containing alkaloids, isolated from a series of marine and terrestrial cyanobacteria. Syntheses of N-methylwelwitindolinone C isothiocyanate (146), C3-hydroxy-N-methylwelwitindolinone C isothiocyanate (147), N-methylwelwitindolinone C isonitrile (148), C3-hydroxy-N-methylwelwitindolinone C isonitrile (149), and N-methylwelwitindolinone D isonitrile (150) were reported by three groups.…”

Mycochemistry of marine algicolous fungi

“…On the other hand, it is worth mentioning that the presence of nitrogen atoms made the structural characterization of some alkaloids challenging. Several of them attracted much attention for total syntheses due to the unique structures, which even resulted in their stereochemical revisions, such as citrinadins A (303) and B (304) (Bian et al 2013;Kong et al 2013). Indole alkaloids (296-324) make up the predominant part, consisting of indole diterpenes, cytochalasans, and other tryptophan derivatives.…”