No abstract

Asymmetric Pd-catalyzed allylic alkylations of dimethyl malonate and diethyl 2-acetoxymalonate with 3-chlorocyclopentene, using phosphanyloxazolines 1 and ent-1 as chiral ligands, gave products (−)-2 and (+)-3b with 95 and 99.5% ee, respectively. Oxidative degradation of (+)-3b furnished (+)-(R)-cyclopent-2-ene-1-carboxylic acid [(+)-4] with Ͼ 99% ee. Alkylation product (−)-2 was transformed into enantio-

Sehr stabile Liposomen sind aus den Lipiden von thermoacidophilen Archaea zugänglich, die aus Mischungen von makrocyclischen, 72‐gliedrigen Tetraethern bestehen. Diese sind aus gesättigten isoprenoiden Ketten und Glycerin oder höheren Zuckern aufgebaut. Durch die Totalsynthese des Diols 1 gelang es erstmals, die Konfiguration eines Lipids mit Cyclopentaneinheiten aufzuklären.

Acid. -Asymmetric palladium-catalyzed allylic alkylations of dimethyl malonates with 3-chlorocyclopentene results in formation of (IV) and (VII) (procedure already known) using phosphanyloxazolines (I) or ent-(I) as chiral ligands. Alkylation product (IV) is transformed into enantiomerically pure (-)-(V) which is used as starting material in the first synthesis of enantiomerically pure (-)-chaulmoogric acid (VI). Acetate (VII) is transformed to acid (VIII) as a potential synthon of natural products. -(SEEMANN, M.; SCHOELLER, M.; KUDIS, S.; HELMCHEN*, G.; Eur.