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Triflic Acid Promoted Transformations of Linear‐Conjugated Enynones and their Reactions with Arenes. Synthesis of Dihydropyranones, Conjugated Dienones, and Indanes
Author(s) -
Zalivatskaya Anna S.,
Golovanov Alexander A.,
Boyarskaya Irina A.,
Kruykova Mariya A.,
Khoroshilova Olesya V.,
Vasilyev Aleksander V.
Publication year - 2021
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.202100280
Subject(s) - chemistry , triflic acid , protonation , conjugated system , acetylene , medicinal chemistry , triple bond , organic chemistry , double bond , photochemistry , catalysis , ion , polymer
Linear‐conjugated enynones,1,5‐diarylpent‐4‐en‐2‐yn‐1‐ones [Ar 2 −CH=CH−C≡C−C(=O)Ar 1 ], have been cyclized into 2,6‐diaryl‐2,3‐dihydropyran‐4‐ones in triflic acid TfOH (CF 3 SO 3 H). Reactions of these enynones with arenes Ar 3 H in TfOH have afforded, at first stage, products of hydroarylation of the acetylene bond, 1,3,5‐triarylpent‐2,4‐dien‐1‐ones [Ar 2 −CH=CH−C(Ar 3 )=CH−C(=O)Ar 1 ], which have been further cyclized into alkylidene indanes. Plausible reaction mechanisms have been proposed. According to quantum chemical calculations by DFT method, initial key reactive intermediates are vinyl type dications [Ar 2 −CH=CH−C + =CH−C(=O + H)Ar 1 ], generated under the protonation of carbonyl oxygen and acetylene bond of starting enynones in TfOH.