(2S,4R)-N-Benzyloxycarbonyl-4-tosyloxyproline methyl ester, readily prepared from commercially available (2S,4R)-N-benzyl-oxycarbonyl-4-hydroxyproline, was converted to (S)-3,4-dehydroproline of high enantiomeric purity by a process which involved a highly regioselective phenylselenoxide elimination to introduce the olefinic function.

Azoxyalkanes were found to be regiospecifically formed in the reactions of some alkyllithium and Grignard reagents with N-nitroso-O,N-dialkylhydroxylamines. Remarkably, although (Z)-stereomers were usually produced, in one case the (E)-isomer was predominant.

Ausgehend von Glycerin wird über mehrere Stufen der Glycerin‐benzyl‐dialkylether (Ia) erhalten, der zu (Ib) hydrogenolysiert wird.

No abstract

Na‐selenid reagiert mit den substituierten Vinylaldehyden (I) und (III) über die Zwischenstufen (II) und (IV) zu den Selenopyranen (V).