Journal of Catalysis, Vol.377, 609-618, 2019
Adamantyl-BINOL as platform for chiral porous polymer aromatic frameworks. Multiple applications as recyclable catalysts
Herein, we report the synthesis of adamantyl-BINOL-based chiral porous aromatic polymers (Ad-BINOL-PAFs) for heterogeneous catalysis. Ad-BINOL-OH-PAF (365 m(2).g(-1)SA(BET)) was built through the covalent bonds among of 4,4'-dibromo-O-ethyl-protected adamantyl-BINOL with 1,3,5-Triphenylbenzene-4',4 '',4'"-triboronic acid and in the presence of [Ti(OiPr)(4)] results an effective recyclable catalyst in the asymmetric addition of diethylzinc to aromatic aldehydes (ee up to 88%). The corresponding heterogenized phosphoric acid (Ad-BINOL-PO2H-PAF) was applied as heterogeneous recyclable organocatalyst for the cascade condensation/amine addition of anthranilamide with aldehydes and transfer hydrogenation reactions obtaining high yields but low enantioselectivity. On the other hand, heterogeneous phosphoric acid (Ad-BINOLs-PO2H-PAF) was also used as effective phosphate ligands for synthesis of rhodium(II) complexes which were effective catalysts in cyclopropanation of styrene affording chiral cyclopropanes in good yield and high diastereoselectivity (>99%) and moderate enantioselectivity (ee < 50%). (C) 2019 Elsevier Inc. All rights reserved.