Isocyano ferrocene

The instability of fc(NH2)2 towards oxidation is certainly the reason that it cannot be used as a building-block for the synthesis of ferrocene-containing polymers [72]. l,T-Di(isocyano)ferrocene, fc(NC)2, has not been described so far. 

The ferrocenyl and ferrocenyl-1-alkyl residues continue to find various applications in organic chemistry, due to the peculiar properties of such residues. Syntheses of isocyano ferrocene 1625 [1213] and of 1-isocyano-l-alkyl ferrocene compounds 1626-1628 [1214] have been described, all of which involve the standard procedure of dehydration of the corresponding formamide with phosphoryl chloride. 

The first example of a C C bond-forming reaction catalysed by gold was the asymmetric aldol condensation developed in 1986.30 The addition of an isocyano acetate to an aldehyde produces the A -oxazole as the major and Z-oxazole as the minor product in excellent enantiomeric excess (ee) in the presence of a cationic gold catalyst, [Au(CyNC)2]BF4, and a chiral diphosphanyl ferrocene ligand (see Scheme 12.5). 

From the linear correlation between and op or the Taft polar o substituent constants recognized for a number of ferrocene derivatives, it was possible to estimate such constants for various isocyanide groups aixl the (high) values obtained (e.g., o ca. 2.8 for -N=C) substantiate the strong electron withdrawing ability of the isocyano group [21]. 

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See also in sourсe #XX -- [ ]

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