D2-Symmetric Chiroporphyrins Derived from (1R)-cis-Hemicaronaldehydic Acid: Preparation and Spectral Characterization

Investigation of the Enantioselectivity Observed in Epoxidation Reactions Catalysed by Bis‐Strapped Chiral Porphyrins Derived from L ‐Proline

“…In light of these instructive but relatively low enantioselectivities, we decided to extend our approach to another family of catalysts. Since 1995, we were aware of a study involving the four atropisomers of a chiral catalyst, synthesised by the condensation of a BINAP‐type aldehyde with pyrrole,24 leading to the aromatic analogues of the well‐known “chiroporphyrins” 25. It was shown in this report that the iron−ααββ atropisomer was the most enantioselective catalyst among the four atropisomers for the epoxidation of styrene (59% ee vs. 7.5% ee for the αβαβ atropisomer).…”

Nickel porphyrin nanotweezers

“…The latter was reacted with pyrrole according to a literature method 4 to afford the bis-strapped chiroporphyrin 3 in 5% yield. ‡ In contrast to the first-generation chiroporphyrins devoid of straps, which are always obtained as the abab atropisomer, 5 3 shows an a 4 conformation with the two 8-methylene straps linking adjacent meso substituents on the same face of the porphyrin. This unusual conformation is apparent in the C 2 symmetry of the NMR spectra of 3 [e.g.…”

Control of Epoxidation Enantioselectivity by Axial Ligation in Manganese Chiroporphyrins with Diastereotopic Faces

“…Pyrrole was purified by filtration through alumina before use. The methyl and benzyl esters of 1 (biocartol esters) were prepared according to previously published procedures 1. Thin‐layer chromatography was performed using Merck precoated silica plates 60F‐254.…”