Expression of concern: Iron oxide magnetic nanoparticles with versatile surface functions based on dopamine anchors.

Expression of concern for 'Iron oxide magnetic nanoparticles with versatile surface functions based on dopamine anchors' by Mykola Mazur , , 2013, , 2692-2702, https://doi.org/10.1039/C3NR33506B.

On the reaction of diaminocarbenes with aroylimines.

Several possible reaction pathways are analyzed for the recently studied experimental reaction of diaminocarbenes with aroylimines, where the carbene acted as an oxygen-abstracting agent. A number of structures corresponding to local minima and transition states are located by geometry optimization. In contrast to the more recent interpretation of the mechanism of this process, the reaction does not proceed via the direct formation of the corresponding carbonyl ylide resulted from the electrophilic addition of diaminocarbene to the carbonyl oxygen atom.

Efficient asymmetric synthesis of trifluoromethylated β-aminophosphonates and their incorporation into dipeptides.

Addition of anions derived from dialkyl methylphosphonates to (Ss)-N-tert-butanesulfinyl (3,3,3)-trifluoroacetaldimine afforded (Ss,R) addition adducts in moderate to good yield (53-75%) with excellent diastereoselectivity (94-95% de). After selective removal of the N-sulfinyl group, dipeptides containing enantiomerically pure diethyl 2-amino-3,3,3-trifluoropropylphosphonate were synthesized to investigate the influence of the trifluoromethyl substituent on N-terminal coupling.