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Proline‐Modified Porphyrin Catalysts for Enantioselective Epoxidations: Design, Synthesis, and Reactivity
Author(s) -
Boitrel Bernard,
BaveuxChambenoît Valérie,
Richard Philippe
Publication year - 2004
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200490219
Subject(s) - chemistry , enantioselective synthesis , stereocenter , porphyrin , amide , catalysis , chirality (physics) , stereochemistry , reactivity (psychology) , proline , molecule , combinatorial chemistry , amino acid , organic chemistry , medicine , biochemistry , chiral symmetry breaking , physics , alternative medicine , pathology , quantum mechanics , quark , nambu–jona lasinio model
The syntheses of various strapped and ‘picket‐fence’ chiral porphyrins are described, and their reactivities towards the enantioselective epoxidation of alkenes are reported. Four L ‐proline residues provide the chirality for the various meso ‐substituted catalysts, which differ by either the spatial arrangement of the stereogenic centers or the nature and length of the straps. The resulting bridged structures possess four amide linkages in each strap, leading to highly rigid molecules with well‐defined geometries whereas the strapped Fe catalysts gave rise to only moderate enantioselectivities, the C 2 ‐symmetrical ones being superior to the D 2 ‐symmetrical compounds. The D 2 ‐symmetrical ‘picket‐fence’ porphyrins were as selective as their strapped counterparts.