Ferrocenyl preparation

Bell and Hall have incorporated an organometallic unit into a crown by using the ferrocenyl unit as part of the ring or as a third strand. The unit is incorporated either as the 1,1 -diformylferrocene or the corresponding acid. In the former case, the bis-imine is prepared and reduced to give the saturated crown (see structure 24). In the latter case, the acid is converted into its corresponding chloride and thence into the diamide by reaction with a diamine. Diborane reduction affords the saturated amino-crown. Structure 24 could be prepared by either of these methods but the dialdehyde approach was reported to be poor compared to the amide approach which afforded the product in ca. 60% yield . 

Thionyl imide, HNSO, is a thermally unstable gas, which polymerizes readily. It can be prepared by the reaction of thionyl chloride with ammonia in the gas phase. Organic derivatives RNSO have higher thermal stability, especially when R = Ar. The typical synthesis involves the reaction of a primary amine or, preferably, a silylated amine with thionyl chloride. A recent example is the preparation of FcNSO (Fc = ferrocenyl) shown in Eq. 9.8. In common with other thionylimines, FcNSO readily undergoes SO2 elimination in the presence of a base, e.g., KO Bu, to give the corresponding sulfur diimide FcNSNFc. 

Since electron-donating substituents at the phosphorus atom favor addition reactions over olefination reactions, addition of 9 to aldehydes leads to the exclusive formation of the silyl-pro-tected allylic alcohols 10. No reaction products arising from Wittig alkenylation could be detected. The ylides (R,S)-9 and (S.S)-9 and their enantiomers were prepared from the corresponding optically pure l-[2-(diphenylphosphino)ferrocenyl]-A,A -dimethylethanamine diastereomers 7 via the phosphonium salts 8. 

The lithium benzamidinates Li[PhC(NR)2] (R = Cy, Pr ) and Li[2,4,6-(Cp3)3C6H2C(NCy)2] have been prepared analogously. Reaction of FcLi (Fc = ferrocenyl) with 1,3-dicyclohexylcarbodiimide ( = DCC, Scheme 6), followed by addition of water, afforded the ferrocene-substituted amidine Fc(NCy)NHCy in 50% yield. The amidine is readily deprotonated by LLN(SiMe3)2 or NaN(SiMe3)2 to yield the alkali metal amidinates, Li[FcC(NCy)2l and Na[FcC(NCy)2l in high yields. ... 

Recently a novel chiral ferrocene-based amidinato ligand and its rhodium complexes have been described. The chiral N,N -bis(ferrocenyl)-substituted formamidine (N,N -bis[(S)-2- (lR)-l-(diphenylphosphino)ethyl ferrocen-l-yl]for-mamidine was prepared from commercially available (IR)-l-(dimethylamino) ethyl ferrocene by a multistep procedure in an overall yield of 29%. Deprotonation of the ligand with -butyllithium followed by addition of [RhCl2(COD)2] as illustrated in Scheme 167 yielded the corresponding (formamidinato)rhodium(l)... 

Peters R, Fischer DF (2005) Preparation and diastereoselective ort/io-metalation of chiral ferrocenyl imidazolines remarkable influence of LDA as metalation additive. Org Lett 7 4137 140... 

The ODNs used here were prepared on an automated DNA synthesizer and with the standard j6-cyanoethyl phosphoramidite coupling reaction. The ferrocenyl ODN (T12Fc) was synthesized by the coupling of amino-terminated ODN with the activated ester of ferrocenecarboxylic acid. A 16 mer ODN (el6S), which has five successive phosphorothioate units on its 5 -terminus, was synthesized using Beaucage s reagent... 

Dithiolene complexes [ Pd(PPh3)2 ra S2C=CCHC(0)R ] are mononuclear or homodinuclear derivatives of ferrocenyl-substituted dithiolene ligands.530 2,2-Diacetyl-1,1-ethylenedithiolato complexes of palladium can be used to prepare dinuclear PdAg and PdAu complexes 531... 

Several new palladium(O) complexes of t-butylphosphine ligands, such as those in Figure 4, have been prepared. For example, the palladium(O) complexes of the parent ferrocenyl ligand113 and of a biarylphosphine191 that was present in Figure 3 have been characterized crystallog-raphically. The palladium(O) complex of the pentaphenylferrocenyl ligand has been identified, but its structure has not been reported.112... 

Hydrazones are also useful substrates in the preparation of pyrazoles. Reaction of N-monosubstituted hydrazones with nitroolefins led to a regioselective synthesis of substituted pyrazoles <060L3505>. lf/-3-Ferrocenyl-l-phenylpyrazole-4-carboxaldehyde was achieved by condensation of acetylferrocene with phenylhydrazine followed by intramolecular cyclization of the hydrazone obtained under Vilsmeier-Haack conditions <06SL2581>. A one-pot synthesis of oxime derivatives of l-phenyl-3-arylpyrazole-4-carboxaldehydes has been accomplished by the Vilsmeier-Haack reaction of acetophenone phenylhydrazones <06SC3479>. 

The dithiophosphonic acid monoesters, RP(OR )(S)SH can be conveniently prepared by cleavage of dimeric, cyclic diphosphetane disulfides, [RP(S)S]2 with alcohols, silanols, or trialkylsilylalcohols180 and then can be converted into metal complexes M[SPR(OR )]2 without isolation.181 The substituted ferrocenyl anion, (N3C6H4CH20)(CpFeC5H4)PS2 has been prepared in two steps from P4Sio, ferrocene and hydroxymethylbenzotriazole (and its salt was used for the preparation of some nickel and rhodium complexes).182 Zwitter-ionic ferrocenylditiophosphonates,... 

The ethynyl-linked complexes 105 were prepared and explored as potential building blocks for nonlinear optical (NLO) materials.129 Spectroscopic and cyclic voltammetry data indicate a small but real interaction between the ferrocenyl donor group and the borabenzene unit, increasing in the order RuHyper-Rayleigh scattering revealed small values for the first hyperpolarizability / , which increases in the same order. 

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