Synthesis of phosphinoferrocenyloxazolines. New ligands for asymmetric catalysis

Ferrocene-derived P,N ligands: synthesis and application in enantioselective catalysis

“…In addition, oxazolines have been shown by various groups to be excellent ortho -directing groups [44][45][46][47]. The origin of diastereoselection is shown in Figure 3.…”

“…This implies that the substituent on the oxazoline moiety has to point downwards in order to avoid sterical repulsion with the incoming n-BuLi molecule. Access towards the other diastereomer with opposite planar chirality is provided via introduction of a temporary protecting group, followed by lithiation and functionalization of the less favored position (Scheme 5) [46].…”

Synthesis, physical and antimicrobial studies of ferrocenyl-N-(pyridinylmethylene)anilines and ferrocenyl-N-(pyridinylmethyl)anilines

“…9 Generally, studies on ferrocene revolve around generation of compounds that are used in materials science, 10 electrochemistry 11,12 catalysis, [13][14][15] medicinal applications [16][17][18][19][20][21][22][23][24] and nonlinear optics 25,26 amongst others. Ferrocene derivatives containing organic fragments bearing one or more heteroatoms such as sulphur, 27 nitrogen, 28 oxygen, 29 and phosphorous 30 have gained prominence. Amongst the N-heterocyclic ferrocenyl metalloligands, ferrocenylpyridine metalloligands have been studied for the possibility of exploiting their redox properties in applications such as amperometric sensors for metal ions 31,32 since they facilitate long-range metal-metal interactions in binuclear complexes.…”

Synthesis of MeO-PEG-Supported Ferrocenyloxazoline Ligands and Their Application in Asymmetric Catalysis

“…According to the known literature procedure, [32] TBS protected oxazoline 6 was conveniently synthesized from ferrocene carboxylic acid and chiral amino alcohol 5. ortho-Lithiation of oxazoline 6 was investigated using n-BuLi in Et 2 O at -78 ℃ , followed by addition of Ar 2 PCl to give the compounds 7 in moderate yields. Then protective group of TBS was removed with TBAF in THF, followed by reaction with poly(ethylene glycol)s 1900 monomethyl ether mesylate in the presence of Cs 2 CO 3 in DMF, giving the PEG supported chiral N,P ligands 8a-8b in 47%-81% yields (Figure 3).…”