Facile conversion of CF3-containing propargylic alcohol derivatives via the corresponding allenes

Ketenes and Other Cumulenes as Reactive Intermediates

“…Trifluoromethyl-substituted allenes 138 are prepared from trifluoromethyl-substituted propargylic tosylates by treatment with appropriate bases (eq ) …”

“…X-ray structure of adduct 142 . Reproduced with permission from ref . Copyright 2012 The Royal Society of Chemistry.…”

Synthesis of Trifluoromethyl-allenes by Gold-Catalyzed Rearrangement of Propargyl Benzyl Ethers

“…From a general point of view, currently available synthetic routes to CF 3 -allenes 1 can be classified into two main categories A and B (Scheme , top). CF 3 -allenes can be prepared starting from alkynyl or alkenyl substrates already possessing a CF 3 moiety (category A ) by elimination reactions, isomerizations, sigmatropic rearrangements, S N 2′ reactions, and metal-catalyzed processes. , A more recently developed alternative access to CF 3 -allenes relies on the use of a “Cu-CF 3 ” reagent to introduce the CF 3 moiety on an activated alkynyl substrate (category B ) . Even if these different methods are complementary with each other and allow an overall access to a variety of functionalized CF 3 -allenes, they are still suffering some limitations mainly in terms of product formation selectivity and substrate accessibility.…”