Premium
Enantioselective Lewis Acid Catalysis in Intramolecular [2+2] Photocycloaddition Reactions of Coumarins
Author(s) -
Guo Hao,
Herdtweck Eberhardt,
Bach Thorsten
Publication year - 2010
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201003619
Subject(s) - intramolecular force , enantioselective synthesis , stereocenter , catalysis , lewis acids and bases , chemistry , yield (engineering) , stereoselectivity , chiral lewis acid , organic chemistry , medicinal chemistry , combinatorial chemistry , physics , thermodynamics
Photochemistry goes acidic! In the presence of the chiral Lewis acid catalyst 2 the intramolecular [2+2] photocycloaddition of 4‐(alk‐4‐enyl)coumarins ( 1 ) provides the corresponding products 3 with up to four stereogenic centers in a highly chemo‐ (84–89 % yield) and stereoselective fashion. For R=H, enantioselectivities up to 82 % ee are possible with 50 mol % catalyst 2 and up to 78 % ee with only 20 mol % of catalyst 2 .