Ferrocenes amino-substituted

Ferrocenylphosphines, chiral. Hayashi et al.1 have prepared a large number of chiral ferrocenylophosphines, which have planar chirality owing to 1,2-unsymmetrical substitution on the ferrocene group. In addition, one of the substituents contains a chiral carbon atom. The most interesting phosphines have amino or hydroxyl groups in the side chain. These phosphines, in combination with transition metals, can promote highly efficient enantioselective reactions. 

Among C(R)-substituted ferrocenes, various derivatives, containing cyano, amino, dialkylamino, amino(dialkylamino)methyl, azide, aldehyde, ketone, rhodanide, and... 

The substituted ferrocenes 757 are widely used as metal-ligand systems. These compounds have a great variety of chelating groups (R) (1-diketones (a) [458], semicarbazones and thiosemicarbazones (b) [458], azomethines and their analogues (c) [458-462], oximes (d), carbonic, thiocarbonic (e), and amino acids (f) [458] ... 

Exploiting the structure-based strategy, the quinuclidinyl and the piperidinyl side chains of quinine (QN) and mefloquine (MF) were, respectively, substituted with a ferrocene moiety while maintaining a basic amino group (Fig. 16). In vitro, lower activities than the parent compounds were reported [106], In acidic aqueous solution, these ferrocenyl analogs seemed to be unstable, leading to the formation of the presumably inactive carbeniums. 

Ligand evaluation continues for enantioselective addition of organozinc reagents to aldehydes, including the substituted BINOL 34, the ferrocene derivative 35, an imine 36 from 2-amino-1,2,2-triphenylethanol, as well as the Cj-symmetric 37 and enf-38. ... 

A solution of 10 mmol (2.57 g) of the racemic amine in 50 mL of /-PrOH is added to a solution of 2.92 g (10 mmol) of (-)-diacetone-2-keto-L-gulonic acid in 150 mL of i-PrOIl at 50 °C. The solution is allowed to come to 20 DC and the precipitated salt is filtered off, washed with Et,0 and recrystallized three times from the smallest possible amount of CH3OH (60 C) the temperature should lower by 2 3 C per hour. The salt is treated with 10% aq NaOH and the liberated amine extracted with Et20. After drying over Na,S04 and evaporation of the solvent, (5)-(1-amino-2-methylpropyl)fenocene is obtained as an oil yield 0.46 g (36%) Md° +90.3 (c = 1, benzene). Substituting i-PrOH for a mixture of acetone/H20 3 1 in the above procedure [14 mL of solvent for both amine (10 mmol) and (—)-diacetoilc-2-kcto-L-gulonic acid (5.0 mmol)] yields (R)-( 1 -amino-2-methylpropyl)ferrocene yield 0.51 g (40%) [a]f,° —90.0 (c = 1, benzene). 

Since amines of type 3 (or the corresponding alcohols as synthetic equivalents) still remain the most versatile starting materials for diastereoselective lithiation processes, and because the amino group can easily be substituted in a process occuring with retention of configuration [3a], methods have been developed for their enantioselective preparation. Recent work includes the aminoal-cohol-catalyzed addition of dialkylzinc reagents to ferrocene-carbaldehyde [7], and the... 

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