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Photochemical and Thermal Isomerization Processes of a Chiral Auxiliary Based Donor–Acceptor Substituted Chiroptical Molecular Switch: Convergent Synthesis, Improved Resolution and Switching Properties
Author(s) -
van Delden Richard A.,
Hurenkamp Johannes H.,
Feringa Ben L.
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200204660
Subject(s) - stereocenter , pyrrolidine , chemistry , molecular switch , photochemistry , steric effects , chiral auxiliary , isomerization , diastereomer , circular dichroism , chirality (physics) , absolute configuration , stereochemistry , enantioselective synthesis , molecule , organic chemistry , physics , catalysis , nambu–jona lasinio model , chiral symmetry breaking , quantum mechanics , quark
A new type of chiroptical molecular switch is presented where irradiation employing different wavelengths of light induces a reversible helix inversion of a sterically overcrowded alkene bearing a second chiral entity in the form of a stereogenic center present in a pyrrolidine unit. The additional stereogenic center in the chiral auxiliary group has a distinct influence on the switching selectivity of this system and greatly facilitates the resolution of the different diastereoisomers, which is a considerable improvement compared with previously reported systems. In addition, the pyrrolidine stereogenic center causes small energetic differences between the various states of the switch system resulting in a small but significant directional preference in the helix inversion steps.