Preparation of Indolenines via Nucleophilic Aromatic Substitution.

An unusual aromatic substitution to access indolenines is described. 2-(2-Methoxyphenyl)acetonitrile derivatives are reacted with various alkyl and aryl Li reagents to furnish the corresponding indolenine products, constituents of natural products, and cyanine dyes such as indocyanine green. This new method was used to synthesize 41 indolenines with large functional group tolerance, and selected examples were further converted to the corresponding indolenine dyes. Key experiments provide insight into the mechanism of this nucleophilic aromatic substitution.

Total Synthesis and Biological Evaluation of the Glycosylated Macrocyclic Antibiotic Mangrolide†A.

The macrocyclic antibiotic mangrolide A has been described to exhibit potent activity against a number of clinically important Gram-negative pathogens. Reported is the first enantioselective total synthesis of mangrolide A and derivatives. Salient features of this synthesis include a highly convergent macrocycle preparation, stereoselective synthesis of the disaccharide moiety, and two ß-selective glycosylations. The synthesis of mangrolide A and its analogues enabled the re-examination of its activity against bacterial pathogens, and only minimal activity was observed.

Formal Total Synthesis of (-)-Jiadifenolide and Synthetic Studies toward seco-Prezizaane-Type Sesquiterpenes.

Synthetic studies toward highly oxygenated seco-prezizaane sesquiterpenes are reported, which culminated in a formal total synthesis of the neurotrophic agent (-)-jiadifenolide. For the construction of the tricyclic core structure, an unusual intramolecular and diastereoselective Nozaki-Hiyama-Kishi reaction involving a ketone as electrophilic coupling partner was developed. In addition, synthetic approaches toward the related natural product (2R)-hydroxy-norneomajucin, featuring a Mn-mediated radical cyclization for the tricycle assembly and a regioselective OH-directed C-H activation are presented.