Hydrodemethoxylation, Hydrodechloration, Hydrodesulfurization, and Hydrodeamination of Neutral (η⁵-X-substituted-cyclohexadienyl)tricarbonylmanganese Complexes (X = OMe, Cl, SPh, NEt₂) upon Treatment with Hydride and Then Acid:  cine and tele Nucleophilic Substitutions

Abstract

Treatment of (η5-X-substituted-cyclohexadienyl)tricarbonylmanganese complexes (X = alkoxy, halogeno, dimethylamino and thio) with hydrides and a proton source gave η5-cyclohexadienyl complexes resulting from a cleavage of the C−O, C−Cl, C−N and C−S bonds: The η3-substituted cyclohexenyl intermediates underwent elimination of an agostic hydrogen and the alkoxy, halogeno, amino, or thio group.

Lithiation/Electrophilic Quench of [(η5‐Cyclohexadienyl)Mn(CO)3]: Versatile Functionalization and Resolution of Planar Chirality in the Organomanganese Series

“…The first cine and tele nucleophilic substitutions of [(η 5 ‐cyclohexadienyl)Mn(CO) 3 ] complexes were developed in 1996 by treatment with hydrides and a proton source,5 and their mechanism was shown to be very close to the cine and tele aromatic nucleophilic substitution (SN Ar ) described for [(η 6 ‐arene)Cr(CO) 3 ] complexes 3d. The discovery of Pd cross‐coupling reactions in the η 5 ‐cyclohexadienyl–Mn series6 enabled ready access to a large variety of substituted η 5 complexes bearing double or triple bonds, aryl, or keto groups linked to the π system.…”

Lithiation/Electrophilic Quench of [(η5‐Cyclohexadienyl)Mn(CO)3]: Versatile Functionalization and Resolution of Planar Chirality in the Organomanganese Series

“…The first cine and tele nucleophilic substitutions of [(η 5 ‐cyclohexadienyl)Mn(CO) 3 ] complexes were developed in 1996 by treatment with hydrides and a proton source,5 and their mechanism was shown to be very close to the cine and tele aromatic nucleophilic substitution (SN Ar ) described for [(η 6 ‐arene)Cr(CO) 3 ] complexes 3d. The discovery of Pd cross‐coupling reactions in the η 5 ‐cyclohexadienyl–Mn series6 enabled ready access to a large variety of substituted η 5 complexes bearing double or triple bonds, aryl, or keto groups linked to the π system.…”

Synthesis of tricarbonyl η6- and η5-[(3-thiophenyl)organo]chromium and -manganese complexes

“…Again, no noticeable change was observed for proton chemical shifts of Cr complexes 1b and 4b (5.87, 5.21 ppm and 5.92, 5.20 ppm, respectively, entries 1 and 2) neither for those of h 6 Mn complexes 2 and 5 (5.22, 5.80 ppm and 5.27, 5.76 ppm, respectively, entries 3 and 4) nor for those of h 6 Mn complexes 3 and 6 (7.65, 6.67 ppm and 7.58, 6.63 ppm respectively, entries 5 and 6). Furthermore, by comparison with the NMR data of monosubstituted arene complexes 7 [12], 8 and 9 [13] (Scheme 4, Table 3), the chemical shifts of Cr complexes 1b and 4b resonated at higher frequencies than those of Scheme 1. Synthesis of Cr complexes 1a and 1b.…”

“…Furthermore the conformation of Cr(CO) 3 tripods are very similar, almost staggered with respect to the thiophenyl groups. Thus, the values of the torsion angles C(5) Ã/C(100) Ã/Cr Ã/C (11), C(7)Ã/C(100) Ã/Cr Ã/C (13) and C(9) Ã/C(100) Ã/Cr Ã/C(12) for 1a (C(100) being the center of the six-membered ring) are 268. The corresponding values C(5) Ã/C(100) Ã/Cr Ã/C (13), C(7) Ã/C(100) Ã/ Cr Ã/C(12) and C(9) Ã/C(100) Ã/Cr Ã/C(11) for 4a are 28, 28 and 278, respectively.…”