LAUSR

Abstract α-Ferrocenylalkyl carbonates were demonstrated to be the species for ferrocenylalkylation reactions. The α-ferrocenylalkyl carbonates FcCH(R)OCOOEt (1a-c, Fc = ferrocenyl) were easily generated in situ by a reaction of the α-ferrocenyl substituted alcohols FcCH(R)OH (5a-c) with equimolar amounts of n-BuLi followed by EtOCOCl in THF or Et2O at 20 °C. Due to the low thermal stability, carbonates 1a-c readily undergo a heterolytical decay furnishing the α-ferrocenyl carbocations FcCH(R)+ (2a-c) and carbonate anion R’OC(O)O− (3). The last one reversibly loses a molecule of CO2 giving rise anion EtO− that is capable of deprotonating a pre-nucleophile NuH (MeCOCH2COMe, dimethyl malonate, etc.) giving rise the corresponding nucleophile Nu−. The interaction between 2a-c and Nu− produces the α-ferrocenylalkylation products FcCH(R)Nu (4a-c) in moderate to high yields. The sequence above is a novel α-ferrocenylalkylation procedure easily proceeding under mild and neutral conditions. Due to these features, it may be useful for α-ferrocenylalkylations of either thermally labile compounds or the substrates susceptible to acidic conditions. The stability of carbonates 1a-c was found to decrease as the stability of the corresponding carbocations 2a-c increases. With 2-mercapto-1-methylimidazole, the α-ferrocenylalkylations proceed as the N-alkylation processes.