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Organocatalytic Stereoselective Addition of Aldehydes to Acylquinolinium Ions
Author(s) -
Mengozzi Luca,
Gualandi Andrea,
Cozzi Pier Giorgio
Publication year - 2016
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.201600284
Subject(s) - chemistry , stereoselectivity , acetaldehyde , yield (engineering) , lewis acids and bases , adduct , catalysis , brønsted–lowry acid–base theory , organic chemistry , organocatalysis , enantioselective synthesis , combinatorial chemistry , ethanol , materials science , metallurgy
A direct and simple activation of quinolines, without isolating unstable intermediates, or using isolated N,O‐acetals in the presence of Lewis or Brønsted acids, is described. The procedure is quite straightforward and allows the addition in a stereoselective manner of different aldehydes to various differently substituted quinolines. The desired products were obtained in 28–76 % yields, with dr values up to 83:17 in favor of the syn isomer, and up to 99 % ee . Studies towards the use of acetaldehyde were also performed with different catalysts and the addition was promoted affording the desired product in 62 % yield with 46 % ee . Finally, deprotection and chemical transformations of the enantioenriched adducts were performed.