1620989-71-0Relevant articles and documents
ABC-type meso-triaryl-substituted subporphyrins
Yoshida, Kota,Mori, Hirotaka,Tanaka, Takayuki,Mori, Tadashi,Osuka, Atsuhiro
, p. 3997 - 4004 (2014/07/08)
ABC-Type subporphyrins 5a-5h, which bear three different meso-aryl substituents, were rationally synthesized by condensation of AB-type tripyrranes and aroyl chlorides. ABC-Type subporphyrins 5i and 5j were synthesized by Pd-catalyzed amination reaction of 4-bromophenyl subporphyrins 5e and 5h, respectively. Comparative studies on these ABC-type subporphyrins with A 3-type subporphyrins and A2B-type subporphyrins revealed that substituent effects are mostly simple superpositions of individual substituents but cooperative effects are recognized for subporphyrins which bear both electron-donating and electron-withdrawing substituents. Despite extensive attempts, enantiomeric separation of B-methoxy ABC-type subporphyrins was unsuccessful, whereas B-phenylated ABC-type subporphyrins were separated to pure enantiomers. Separated enantiomers showed weak but distinct CD signals reflecting the chiral clockwise/anticlockwise arrangements of the meso-aryl substituents. These results suggest facile racemization through S N1-type heterolysis of the B-OMe bond in solution. ABC-Type meso-triaryl-substituted subporphyrins were rationally synthesized. Cooperative substituent effects are noted for donor-acceptor-type subporphyrins. Although the chiral resolution has not been successful for B-methoxy ABC-type subporphyrins, the enantiomers of some B-phenyl subporphyrins have been resolved by using chiral HPLC. Copyright