Supramolecular bidentate rhodium(i) or iridium(i) phosphine and oxazoline amino acid bioconjugates as selective catalysts for enantioselective reactions

Bakija, Marija; Opačak, Saša; Perić, Berislav; Chakrabortty, Soumyadeep; Dell'Acqua, Andrea; Baráth, Eszter; de Vries, Johannes G.; Tin, Sergey; Kirin, Srećko (2024) Supramolecular bidentate rhodium(i) or iridium(i) phosphine and oxazoline amino acid bioconjugates as selective catalysts for enantioselective reactions. Dalton Transactions . ISSN 1477-9226

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Abstract

This publication describes monodentate phosphine and oxazoline ligands attached to an amino acid ester and the application of their supramolecularly assembled rhodium(I) or iridium(I) complexes in asymmetric catalysis. The major feature of these complexes is the transmission of chirality from distant hydrogen bonded amino acids to the prochiral catalytic metal center (“backdoor induction”). The in situ generated homoleptic and heteroleptic rhodium(I) or iridium(I) precatalysts were studied by NMR, UV-VIS and CD spectroscopy as well as X-ray single crystal diffraction. In asymmetric hydrogenation of methyl α-acetamidocinnamate, rhodium(I) and iridium(I) complexes afforded complete conversions with enantioselectivities up to 85%, while iridium complexes proved to be more sensitive to the variation of reaction conditions, including catalyst loading, metal to ligand ratio and temperature. The hydrogenation of four other dehydroamino acid substrates resulted in similar conversion and selectivity as obtained with methyl α-acetamidocinnamate. The influence of the phosphine/oxazoline heteroleptic mixtures in catalysis was studied using both rhodium(I) and iridium(I) complexes. Finally, a homoleptic phosphine rhodium(I) complex was successfully applied in asymmetric hydroformylation of styrene and 1-octene with complete conversions and selectivity up to 40% ee for the branched styrene product.

Item Type:	Article
Uncontrolled Keywords:	iridium(I) complex; rhodium(I) complex; triphenylphosphine ligands; oxazoline ligands; amino acid bioconjugates; hydrogen bonding; homogenous asymmetric hydrogenation; asymmetric hydroformylation.
Subjects:	NATURAL SCIENCES > Chemistry
Divisions:	Division of Materials Chemistry
Projects:	Project title Project leader Project code Project type Inovativna rješenja u katalitičkim proizvodnim procesima za potrebe farmaceutske industrije-CAT PHARMA Srećko Kirin KK.01.1.1.04.0013 EK Supramolekulska asimetrična kataliza: Prijenos kiralnosti u koordinacijskim kavezima (Cage Cat), program "Istraživački projekti" Srećko Kirin IP-2022- 10-8456 HrZZ
Depositing User:	Marija Bakija
Date Deposited:	05 Dec 2024 15:12
URI:	http://fulir.irb.hr/id/eprint/9341
DOI:	10.1039/d4dt02519a

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