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Repetierbare Ringerweiterungen durch [2,3]‐sigmatropische Umlagerungen in cyclischen Allylsulfonium‐allyliden; Synthese von mittleren und grossen Thiacyclen. Vorläufige Mitteilung
Author(s) -
Schmid Rudolf,
Schmid Hans
Publication year - 1977
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19770600424
Subject(s) - chemistry , sigmatropic reaction , ring (chemistry) , ylide , potassium hydroxide , medicinal chemistry , bromide , stereochemistry , organic chemistry
Repeatable ring expansions by [2,3]‐sigmatropic shifts in cyclic allylsulfonium allylides; synthesis of medium‐ and large‐sized thiacycles Allylation of a 2‐vinyl thiacyclus with allyl bromide in 2,2,2‐trifluoroethanol followed by ylide generation by use of aqueous potassium hydroxide results in a [2,3]‐sigmatropic rearrangement with formation of a new 2‐vinyl thiacyclus enlarged by three carbon atoms ( Scheme 1 ). In this way, starting from the 5‐membered ring 1 , a series of four ring enlargement sequences leads to the 17‐membered thiacycles 9 and 10 via the 8‐, 11‐ and 14‐membered rings 4 , 7 and 8 (Scheme 2) .