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Reactions of Trifluoroacetyl Alkynes Under Electrophilic Activation with Brønsted Acids or Acidic Zeolites
Author(s) -
Nursahedova Selbi K.,
Ryabukhin Dmitry S.,
Muzalevskiy Vasily M.,
Iakovenko Roman O.,
Boyarskaya Irina A.,
Starova Galina L.,
Nenajdenko Valentine G.,
Vasilyev Aleksander V.
Publication year - 2019
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201801645
Subject(s) - chemistry , yield (engineering) , electrophile , cationic polymerization , adduct , pyridine , medicinal chemistry , stereoselectivity , acetylene , hydrolysis , organic chemistry , catalysis , materials science , metallurgy
The reaction of trifluoroacetyl alkynes [ArC≡C(C=O)CF 3 ] with H 2 SO 4 or TfOH affords products of addition of the acids to the acetylene bond. Hydrolysis of these adducts results in the formation of the corresponding 1,3‐diketones existing in form of enols [Ar(HO)C=CH(C=O)CF 3 ] in up to 98 % yield. The application of less acidic TfOH‐pyridine system permits transformation of these alkynes into the corresponding vinyl triflates in up to 76 % yield. Moreover, this reaction is totally stereoselective to give only Z‐configured vinyl triflates. The reaction of trifluoroacetyl alkynes with arenes in TfOH or under the action of acidic HUSY zeolites CBV‐720 gives rise to 1,3‐diaryl‐1‐CF 3 ‐indenes in up to 81 % yield. Electronic characteristics of initial intermediate mono‐ and dicationic species derived from such alkynes in the highly acidic media were studied by DFT calculations. Plausible cationic reaction mechanism was proposed.