Usinggas chromatography with flame ionization detection (FID) and electroantennographic detection (EAD) in parallel, butanoic acid, skatole, and (E)-2,6-dimethyl-6-octen-2-ol were identified as constituents of the abdominal sex-attracting secretion of the male dung beetle, Kheper subaeneus, which reproducibly elicited EAD responses in male and female antennae. This is the first report of the occurrence of (E)-2,6-dimethyl-6-octen-2-ol as a natural product, for which the name (E)-subaeneol is proposed. In some experiments, a few other constituents of the secretion also gave reproducible responses in specific male and female antennae but did not elicit responses when the analyses were repeated with other antennae. The major volatile constituent of the secretion, identified as (S)-(C)-2,6-dimethyl-5-heptenoic acid, is one of these EAD-active compounds. Both this compound and (E)-2,6-dimethyl-6-octen-2-ol were synthesized from authentic starting materials for comparison with the natural products.
Synthesis of Tetrahydronaphthyridines from Aldehydes and HARP Reagents via Radical Pictet–Spengler Reactions
作者:Moritz K. Jackl、Imants Kreituss、Jeffrey W. Bode
DOI:10.1021/acs.orglett.6b00523
日期:2016.4.15
with newly designed HARP (halogen amine radical protocol) reagents gives access to α-substituted tetrahydronaphthyridines. By using different HARP reagents, various regioisomeric structures can be prepared in a single operation. These products, which are of high value in medicinal chemistry, are formed in a predictable manner via a formal Pictet–Spenglerreaction of electron-poor pyridines that would
[figure: see text] The first total synthesis of (-)-stellettamide B has been achieved by a sequence based on amide coupling of the chiral 1-(aminomethyl)-indolizidine fragment, prepared by TiCl4-mediated asymmetric allylation of the tricyclic N-acyl-N,O-acetal, with the chiral trienoic acid fragment. This synthesis led to revision of the published relative stereochemistry of the natural product and established
[GRAPHICS]AlMe3 dramatically increases the diastereoselectivity of addition of vinyllithiums to alpha-chiral aldehydes but decreases that of methyllithium. Our results are explained in terms of an addition of the free vinyllithium on the Me3Al-aldehyde complex.
KULICKE, KLAUS JURGEN;GIESE, BERND, SYNLETT.,(1990) N, C. 91-92