Studies on Horner-Wadsworth-Emmons reaction in base sensitive ketones: Synthesis of (−)-mitsugashiwalactone and formal synthesis of (+)-iridomyrmecin, (−)-isoiridomyrmecin and (+)-teucriumlactone

Catalytic Enantioselective Friedel−Crafts Alkylations of Indoles with α‘-Phosphoric Enones

The C2-symmetric bis(oxazoline) copper(II) complex proves to be an excellent catalyst in the Friedel-Crafts alkylation of indoles with alpha'-phosphoric enones. The enantioselectivities of this reaction are obtained in up to 98% ee.

Iridoids from the aerial parts of Verbena littoralis (Verbenaceae)

The iridoids, 6S-hydroxy-8S-methyl-4-methylene-hexahydro-cyclopenta[c]pyran-3-one and 6S,9S-dihydroxy-8S-methyl-4-methylene-hexahydro-cyclopenta[c]pyran-3-one, were isolated from the aerial parts of Verbena littoralis. Their structures and stereochemistry were elucidated by means of NMR spectral data analysis. Both compounds showed moderate in vitro activity against gram positive and negative bacteria as well as moderate in vivo intestinal peristaltic action in mouse. The iridoids also showed moderate free radical scavenging activity against l,l-diphenyl-2-picrylhydrazyl (DPPH) as well as antioxidant activity, the latter being evidenced by redox properties measured using E1CD-HPLC.

Synthesis of the Putative Structure of Eupomatilone-6

[reaction: see text] The synthesis of eupomatilone-6 (1) has been achieved by using Suzuki coupling, Sharpless asymmetric dihydroxylation, and intramolecular Horner-Wadsworth-Emmons reactions. The spectroscopic studies carried out on synthetic eupomatilone-6 do not agree with those reported for the natural product, and therefore revision of the assigned structure is warranted.