Ferrocene compounds. XXVI. C- and O-ferrocenylalkylation of methyl salicylate

Reaction of equimolar amounts of methyl salicylate, sodium and N,N,N-trimet hylferrocyl ammonium iodide (la) in ethanol gave 55% of ethyl 1-ferrocenyle thyl ether (4). By refluxing a solution of 9 mmol sodium and 3 mmol of FcCH RNMe(3)I (la, R = H; Ib, R = Me; Ic, R = Ph) in a large excess of methyl sa licylate for 23 hours, the corresponding methyl 5-ferrocylsalicylates (5) ( 10-23%) and methyl-3-ferrocylsalicylates (6) (12-20%) were obtained. During conversion of salt Ib, besides of 5b and 6b, 20% of vinylferrocene (7) and 6% of 1-ferrocenylethyl methyl ether (8) were isolated. Under the same con ditions as in conversions 1 --> 5, 6 2-ferrocenylethyl acetate (11) and met hyl salicylate failed to react, and 2-ferrocenylethyl bromide (12) was tran sformed to 12% of methyl o-(2-ferrocenylethoxy)benzoate (13) and 25% of met hyl 5-(2-ferrocenylethyl)salicylate (14), as well as 10% of vinylferrocene (7). The mechanisms of reactions 1 --> 5, 6 and 12 --> 13, 14 are discussed , suggesting a stabilization effect by ferrocene nucleus in the intermediat e alpha- and beta-ferrocenyl carbocations.