Synthesis and reactivity of alpha-heteroatom substituted organoiron compounds

The work described herein was initially stimulated by reports of amine-modified Fischer-Tropsch reactions. Since iron-alkylidene complexes are important intermediates in Fischer-Tropsch chemistry, the formation of an aminomethyl compound by attack of ammonia on a carbenoid is likely to be an important step in the amine-modified process.; CpFe(CO){dollar}sb2{dollar}CH{dollar}sb2{dollar}N(CH{dollar}sb2{dollar}C{dollar}sb6{dollar}H{dollar}sb5{dollar}){dollar}sb2{dollar}, CpFe(CO){dollar}sb2{dollar}CH{dollar}sb2{dollar}NPhth (Phth = Phthalimido), and CpFe(CO){dollar}sb2{dollar}CN were synthesized with a view to converting them into CpFe(CO){dollar}sb2{dollar}CH{dollar}sb2{dollar}NH{dollar}sb2{dollar}. All attempts to accomplish this transformation met with failure. Similarly, unsuccessful attempts were made to convert CpFe(CO){dollar}sb2{dollar}CH{dollar}sb2{dollar}Cl to the aminomethyl species by Ag(I) or Tl(I)-promoted substitution of chloride by ammonia. However, tertiary amines, phosphines, phosphites, and sulfides reacted with CpFe(CO){dollar}sb2{dollar}CH{dollar}sb2{dollar}Cl, at room temperature in methylene chloride, in the presence of TlBF{dollar}sb4{dollar} to give the corresponding onium salts in excellent yields. These compounds were characterized and their reactivity was examined.; (CpFe(CO){dollar}sb2{dollar}CH{dollar}sb2{dollar}SPh{dollar}sb2{dollar}) BF{dollar}sb4{dollar} was shown to be a good reagent for the cyclopropanation of olefins. Olefins that are not electron-poor were converted to cyclopropanes rapidly and in good yield. A study of the kinetics of the cyclopropanation of cyclooctene by this species showed that the reaction proceeded by an equilibrium dissociation of Ph{dollar}sb2{dollar}S, followed by the reaction of the iron-alkylidene with cyclooctene. The rate constants were determined. Some intramolecular cyclopropanation occurred with the 5-hexenyl phenyl sulfonium iron species, but attempts to isolate cyclopropanes from (CpFe(CO){dollar}sb2{dollar}CH{dollar}sb2{dollar}S(Ph)CH{dollar}sb2{dollar}CH=CH{dollar}sb2{dollar}) BF{dollar}sb4{dollar} were unsuccessful. The latter species was converted to (CpFe(CO)CH{dollar}sb2{dollar}S(Ph)CH{dollar}sb2{dollar}CH=CH{dollar}sb2{dollar}) BF{dollar}sb4{dollar} by photolysis in methylene chloride. This compound decomposed when heated in ClCH{dollar}sb2{dollar}CH{dollar}sb2{dollar}Cl to yield 2-propenyl, 2-methyl-2-propenyl and 3-butenyl phenyl sulfides. (CpFe(CO)S(Ph)CH{dollar}sb2{dollar}CH{dollar}sb2{dollar}CH=CH{dollar}sb2{dollar}) BF{dollar}sb4{dollar} was isolated as an intermediate in this reaction and its crystal structure was elucidated.; The investigation of the mechanism of this decomposition,m including the synthesis, characterization and decomposition of (CpFe(CO)CH{dollar}sb2{dollar}S(Ph)CH{dollar}sb2{dollar}CH=CD{dollar}sb2{dollar}) BF{dollar}sb4{dollar}, indicated that the major reaction pathway involved the stereospecific formation of an alkyl-allyl-iron species.