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Stereoselectivity in Ene Reactions with 1 O 2 : Matrix Effects in Polymer Supports, Photo‐oxygenation of Organic Salts and Asymmetric Synthesis
Author(s) -
Griesbeck Axel G.,
Bartoschek Anna,
Neudörfl Jörg,
Miara Claus
Publication year - 2006
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/2006-03-03-ra-832
Subject(s) - ene reaction , singlet oxygen , chemistry , stereoselectivity , polymer , asymmetric induction , polystyrene , photochemistry , oxygen , polymer chemistry , enantioselective synthesis , organic chemistry , catalysis
The ene reaction of chiral allylic alcohols is applied as a tool for the investigation of intrapolymer effects by means of the stereoselectivity of the singlet‐oxygen addition. The diastereo selectivity strongly depends on the structure of the polymer, the substrate loading degree and also on the degree of conversion demonstrating additional supramolecular effects evolving during the reaction. The efficiency and the stability of polymer‐bound sensitizers were evaluated by the ene reaction of singlet oxygen with citronellol. The ene reaction with chiral ammonium salts of tiglic acid was conducted under solution phase conditions or in polystyrene beads under chiral contact ion‐pair conditions. The products thus obtained precipitate during the photoreaction as ammonium salts. Moderate asymmetric induction was observed for this procedure for the first time.