Szymon Jarzyński

The course of the reactions of acetylenes with fluorinated nitrones in the presence of Zn(OTf)₂ and Et₂Zn was investigated. The formation of hydroxylamines and/or 1,2-oxazolines as products was observed. The desired hydroxylamines were formed as main products if reactions were carried out with the usage of Et₂Zn. In order to explain the obtained results, quantum mechanical calculations of the reaction paths leading to both products were carried out. Further research allowed us to develop the enantioselective variant of described reactions with the usage of enantiomerically pure AziPhenol ligand bearing chiral aziridine scaffold.

The introduction of fluorine atom has attracted considerable interest in molecular design owing to the high electronegativity and the resulting polarization of carbon–fluorine bonds. Simultaneously, sterically‐hindered N‐heterocyclic carbenes (NHCs) have received major interest due to high stabilization of the reactive metal centers, which has paved the way for the synthesis of stable and reactive organometallic compounds with broad applications in main group chemistry, inorganic synthesis and transition‐metal‐catalysis. Herein, we report the first class of sterically‐hindered, fluorinated N‐heterocyclic carbenes. These ligands feature variable fluorine substitution at the N‐aromatic wingtip, permitting to rationally vary steric and electronic characteristics of the carbene center imparted by the fluorine atom. An efficient, one‐pot synthesis of fluorinated IPr*^F ligands is presented, enabling broad access of academic and industrial researchers to the fluorinated ligands. The evaluation of steric, electron‐donating and π‐accepting properties as well as coordination chemistry to Au(I), Rh(I) and Se is presented. Considering the unique properties of carbon–fluorine bonds, we anticipate that this novel class of fluorinated carbene ligands will find widespread application in stabilizing reactive metal centers.

Metal-N-heterocyclic carbene (M-NHC) complexes are well-known as an important class of organometallic compounds widely used in transition-metal catalysis. Taking into account that the steric hindrance around the metal center is one of the major effects in M-NHC catalysis, the development of new, sterically hindered M-NHC complexes is an ongoing interest in this field of research. Herein, we report the synthesis and characterization of exceedingly sterically hindered, well-defined, air- and moisture-stable Cu(I) and Ag(I) complexes, [Cu(NHC)Cl] and [Ag(NHC)Cl], in the recently discovered IPr^# family of ligands that hinge upon modular peralkylation of anilines. The complexes in both the BIAN and IPr families of ligands are reported. X-ray crystallographic analyses and computational studies were conducted to determine steric effects, Frontier molecular orbitals, and bond orders. The complexes were evaluated in the model hydroboration of the alkynes. We identified [Cu(BIAN-IPr^#)Cl] and [Ag(BIAN-IPr^#)Cl] as highly reactive catalysts with the reactivity outperforming the classical IPr and IPr*. Considering the attractive features of well-defined Cu(I)-NHC and Ag(I)-NHC complexes, this class of sterically bulky yet wingtip-flexible complexes will be of interest for catalytic processes in various areas of organic synthesis and catalysis.

Novel transition metallocarbonyl complexes carrying a norbornene or an oxanorbornene group were synthesized by [4 + 2] cycloaddition between the organometallic maleimide dienophiles and cyclopentadiene or furan, respectively. The oxanorbornene adduct was obtained as a mixture of endo and exo isomers as confirmed by X‐ray diffraction and NMR spectroscopy. The (oxa)norbornene groups further provided convenient chemical reporters to carry out inverse electron demand Diels‐Alder (iEDDA) reactions with tetrazine derivatives. Detailed kinetic studies with a model tetrazine revealed that faster rates of reaction were determined with both isomers of the oxanorbornene complex with respect to the norbornene complexes. Eventually, incorporation of metallocarbonyl entities into bovine serum albumin equipped with tetrazine handles was achieved as shown by IR spectroscopy of the protein conjugates.