Eine ungewöhnliche Cl-F-Austauschreaktion bei halogenalkylthioetherketonen

The syntheses of ∝ - sulfinated compounds are described. Their reactions with HF are investigated. A Cl/F-exchange reaction with a spontaneous rearrangement into a β-fluorinated thioethercarbonylfluoride was observed. Factors influencing the reaction and the mechanism are discussed.     

Synthese und ungewöhnliche Reaktivität eines Cyclotrisilans

Reductive coupling of dichlorosilane 1 with magnesium yields the stable, highly moisture sensitive cyclotrisilane 2a. The hydrolysis products, 1,3-siloxanediol 3 and disilane 4 corroborate the proposed structure of 2a. The reaction with typical silylene trapping agents like benzyl, benzophenone or 2,2′-bipyridyl results in cleavage of all three endocyclic bonds of 2a, yielding the formal silylene addition products 8, 9 and 10.     

Über eine ungewöhnliche Cyclisationsreaktion bei der Umsetzung von (+)-Epoxy-α-dihydrojonon mit Hydrazinhydrat

(+)-Epoxy-α-dihydroionone ( 2 ) is formed completely stereospecifically from (+)-α-ionone ( 1 ). Under the conditions of the Wharton reaction this epoxide gives the expected isomeric allyl alcohols 4 and 5 and, surprisingly, the bicyclic allyl alcohol 3 . The structure and absolute configuration of the reaction products have been established. A common intermediate for the formation of compounds 3, 4 and 5 is probably the vinyl anion C.