Robert S. Bly

The preparation and acetolysis of some [π-phenylchromium tricarbonyl]benzyl p-toluenesulfonates and their noncomplexed analogs. a search for σπ delocalization☆

Abstract The substituted benzyl tosylates p-phenyl, p-(π-phenylchromium tricarbonyl), p-(p′-nitrophenyl), m-phenyl, m-(π-phenylchromium tricarbonyl) and m-(p′-nitrophenyl) have been prepared and their solvolysis rates in buffered and/or unbuffered acetic acid determined. At 69.0°C their reactivities relative to benzyl tosylate (1.00) are: 10.8, 7.14, 0.742, 0.571, 0.134 and 0.173, respectively. Conjugative substituent parameters are calculated at 69°C for p-nitrophenyl (σm+ 0.221, σp+ 0.060) and π-phenylchromium tricarbonyl (σm+ 0.262, σp+(0.144). The ability of α-(π-phenylchromium tricarbonyl) to stabilize electrophilic centers is compared with that of α-ferrocenyl and mechanisms of electron donation are discussed.

The reaction of iron-alkyls with triethyloxonium tetrafluoroborate: Formation of iron ethoxycarbene complexes

Abstract At room temperature under an atmosphere of carbon monoxide the iron alkyls, (η 5 C 5 H 5 )(CO) 2 Fe-R (R = CH 2 CH 3 , CH 2 CH 2 CH 3 , CH 2 CH 2 CH(CH 3 ) 2 , CH 2 CH 2 C(CH 3 ) 3 ) react with triethyloxonium tetrafluoroborate to provide the iron ethoxycarbenes, (η 5 -C 5 H 5 (CO) 2 Fe + =C(OEt)(R)BF 4 − in moderate to very good yield.

Methyl and phenyl rearrangements in acyclic FeII alkylidenes

Dicarbonyl(η5-cyclopentadienyl)-(2,2-dimethylpropylidene)iron(II) and -(2-methyl-2-phenylpropylidene)iron(II) tetrafluoroborates, (6) and (10), prepared by protonation of the analogous FeIIα-ethoxyalkyls, rearrange to dicarbonyl(η5-cyclopentadienyl)-(η2-2-methylbut-2-ene)iron(II) and -(η2-2-methyl-1-phenylprop-1-ene)iron(II) tetrafluoroborates, (7) and (11), by shift of a methyl and phenyl group, respectively, from the β to the α carbon atom.