Stereoselective synthesis of planar chiral 2,2′-diarylsubstituted ferrocene derivatives as precursors for new 2-phospha[3]ferrocenophanes

Phosphine Organocatalysis

“…In 2008, Marinetti synthesized the chiral phosphine P47 , featuring a ferrocene backbone, and reported its use for inducing high levels of enantioselectivity in [3 + 2] annulations of chalcones (Scheme ). , Low regioselectivity ensued when an acrylate was used as the electrophilic partner. To achieve higher regioselectivity, substrate control was required.…”

A New Class of C2‐Symmetric Chiral Cyclopentadienyl Ligand Derived from Ferrocene Scaffold: Design, Synthesis and Application

“…Besides the above 2,2′‐dimethyl and 1,1′‐disilyl ferrocenyl Cp ligands 7 a – d , we also successfully synthesized 1,1′‐dialkoxyferrocenyl Cp ligands 7 g – h . As illustrated in Scheme 3, according to our sequential chlorination and Cp installation protocol, the diiodoferrocene 5 e obtained from the highly diastereoselective iodination [29] of diaminoferrocene 4 could be conveniently transformed to the ferrocenyl Cp product as an inseparable mixture of 6 e and 7 e ( 6 e / 7 e =3:1) in 49 % yield over two steps. By treating this mixture with HOAc and cupric oxide, the diacetoxylated product 6 f was obtained in 64 % yield (based on the amount of 6 e ) [30] .…”

Twofold Ferrocene C–H Lithiations For One-Step Difunctionalizations

“…By using sec-butyllithium in diethyl ether, the reaction takes place in good yield and excellent diastereoselectivity, as demonstrated by quenching the dilithio product with 1,2-dibromo-1,1,2,2-tetrachloroethane, 55 chlorosilanes, 55,56 and iodine. 57 It could be deduced from the configuration displayed by the major stereoisomer that a chiral induction similar to that exhibited by the pyrrolidine group during the monofunctionalization of (S)-[2-(methoxymethyl)pyrrolidino]ferrocene using butyllithium takes place. 58 Scheme 17 Dideprotolithiation of (S,S)-1,1′-bis[2-(methoxymethyl)pyrrolidino]ferrocene by using different alkyllithiums.…”