Highly Selective Negishi Cross‐Coupling Reaction of a Zinc‐Metallated Ferrocenyl p‐Tolyl Sulfoxide: New Chiral Ferrocene‐Based Quinone Ligands

Abstract

A highly selective Negishi coupling of zinc-metallated ferrocenyl p-tolyl sulfoxide with aryl bromides was developed. With Pd(PPh 3 ) 4 as catalyst, a well-matched system in terms of reactivity of organometallic compound, aryl bromide, and catalyst, was obtained. The scope of the reaction was studied by the use of aryl bromides 7a−g, which afforded high yields of coupling products. The reaction conditions for the preparation of ferrocenyl p-tolyl sulfoxide, according to the Andersen method, were optimised to give a yield of 80% and an enantio-

Synthesis of planar chiral ferrocenyl sulfides and evaluation as catalysts for the asymmetric epoxidation of aldehydes

“…An entry to an ortho-chain was to treat the sulfinylferrocene anion with a carbonyl compound, such as benzophenone (Scheme 4), affording hydroxyferrocene 4f. For the introduction of an aryl group, two precedent were reported, 31 …”

“…of t-BuOK in THF. 30,31 Subsequent reaction of the cannulated metallated species with the thiosulfinate furnished sulfoxide 2 in 68% yield (e.e. 95-100%).…”

FT-IR, NMR spectroscopic and quantum mechanical investigations of two ferrocene derivatives

“…Because of the redox potential of the ferrocene, different types of organic materials which contain ferrocene moiety were prepared and used in several applications [1][2][3][4][5][6][7]. On the other hand, some ligands and complexes including ferrocene moiety were prepared for the inorganic applications [8][9][10][11]. Ferrocenoyl amino acids and peptides were prepared using acyl ferrocenes and investigated in detail [12][13][14][15].…”

Metallocene Sulfoxides as Precursors of Metallocenes with Planar Chirality

“…Bäckvall et al reported an improved procedure giving 4a in 80 % yield (98 % ee) by slow addition of 1 equivalent of lithiated ferrocene at À60 8C on sulfinate in a more diluted system. [25] Sulfoxides 4b-d were prepared from diastereochemically and enantiomerically pure sulfinates 11 where the chiral group R' is derived from a chiral diol or a carbohydrate. [4,14,25,26] Thus the two enantiomers of 4c have been prepared by the DAG technology (R = Me, R' = DAG or diacetonideglucosyl).…”

“…[25] Sulfoxides 4b-d were prepared from diastereochemically and enantiomerically pure sulfinates 11 where the chiral group R' is derived from a chiral diol or a carbohydrate. [4,14,25,26] Thus the two enantiomers of 4c have been prepared by the DAG technology (R = Me, R' = DAG or diacetonideglucosyl). Sulfoxide 4b is now easily available from the reaction between 8 and the Ellmans reagent t-Bu-S(O)-S-t-Bu.…”