Reactions of ferrocenyl-stabilised carbocations with water: substituent, medium, salt, and solvent isotope effects on rates and equilibria

Synthesis of a ferrocenyl uracil PNA monomer for insertion into PNA sequences

“…Interestingly, we recently found that 5 was a side-product of the coupling of (ferrocenylmethyl)trimethylammonium iodide and 1,4,7-(triformyl)-1,4,7,10-tetraazacyclododecane to give 1-(ferrocenemethyl)-4,7,10-(triformyl)-1,4,7, 10-tetraazacyclododecane in aqueous solution [27]. A possible pathway for the formation of 3-5 is presented in Scheme 1 and involves the simultaneous formation of 3 and the carbocation 6 which has been previously reported to be stabilised in acidic media [28][29][30][31]. Interestingly, the fact that both 3 and 4 were formed suggests that the cleavage of ferrocenyl group is faster than the cleavage of the tert-butyl group as 2 would have been isolated if the cleavage of the ester was faster.…”

Products of hydrolysis of (ferrocenylmethyl)trimethylammonium iodide: Synthesis of hydroxymethylferrocene and bis(ferrocenylmethyl) ether

“…In our case, the presence of the amine 2 may make the reaction mixture sufficiently basic for the hydrolysis of 1-4 to take place. The formation of 5 could involve attack by the oxygen atom of 4 at the methylene carbon of 1, whilst the other would involve a similar attack on another molecule of 4 rather than a mechanism involving a carbocation [8,[12][13][14].…”

Stereoselective synthesis of some chiral ?-ferrocenyl carbenium ions

“…A slow decomposition occurs in polar aprotic solvents, as already mentioned for various ␣ferrocenylcarbenium ions 2. 2,7 The crystalline triflate salt 18e is the most convenient to handle,the other salts 18 being amorphous.…”

“…NMR spectra could not be recorded because of paramagnetic impurities. El-SM: 292 (9%); 291 (100%, M + ); 290 and 289 (38); 288 (7); 188 (6); 187 (26); 186 (53); 185 (9); 184 (4); 171 (7); 170 (6); 169 (7); 130 (11); 129 (8); 125 (6); 120 (5); 110 (9).…”

“…An X-ray structure of 2 showed a bent structure which may be assigned to the mesomeric formula A and B 5 (Scheme 2). Many ␣-ferrocenylcarbenium ions are stable enough to be isolated, 6,7 however, in solution some are slowly decomposed by dimerization of radical type B or by other processes. 7 There are almost no examples of isolated chiral ␣-ferrocenylcarbenium ions.…”