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Title: Addition, cycloaddition, and metathesis reactions of the cationic carbyne complexes [Cp(CO)[sub 2]Mn[triple bond]CCH[sub 2]R][sup +] and neutral vinylidene complexes Cp(CO)[sub 2]M=C=C(H)R (M = Mn, Re)

Journal Article · · Organometallics; (United States)
DOI:https://doi.org/10.1021/om00015a019· OSTI ID:7267468
; ; ;  [1]; ; ;  [2]; ; ;  [3]
  1. Pennsylvania State Univ., University Park, PA (United States)
  2. Laboratoire de Chimie de Coordination du CNRS, Toulouse (France)
  3. Univ. of Delaware, Newark, DE (United States)

The cationic alkylidyne complexes [Cp(CO)[sub 2]M=VCCH[sub 2]R][sup +] (M = Re, R = H; M = Mn, R = H, Me, Ph) undergo facile deprotonation to give the corresponding neutral vinylidene complexes Cp(CO)[sub 2]M=C=C(H)R. For [Cp(CO)[sub 2]Re=VCCH[sub 3]][sup +], this transformation occurs spontaneously at [minus]78[degree]C upon the addition of solvent (CH[sub 2]Cl[sub 2] or THF) to the solid carbyne complex, but the manganese complexes [Cp(CO)[sub 2]Mn=VCCH[sub 2]R][sup +] (R = H, Me) require the addition of external base (e.g., Et[sub 3]N) to induce their deprotonation. The manganese benzylcarbyne complex [Cp(CO)[sub 2]Mn=VCCH[sub 2]Ph][sup +] is intermediate in behavior. Except for Cp(CO)[sub 2]Mn=C=C(H)Ph, these vinylidene complexes are thermally unstable and must be generated and studied at low temperature. They are potent dipolarophiles which undergo net [2 + 2] cycloaddition with imines to give cyclic carbene complexes of the general form Cp(CO)[sub 2]M=CC(H)RC(H)PhN(R)[prime] (M = Re, R = H, R[prime] = Me, Ph; M = Mn, R[prime] = Ph, R = H (17a), Me, Ph (17c)). Identical manganese products form upon treatment of the manganese carbyne complexes first with imine followed by addition of Et[sub 3]N. Permanganate oxidation of the manganese cyclic carbene complexes gives the corresponding [beta]-lactams in excellent yield. Also formed in the reactions of the rhenium complex Cp(CO)[sub 2]Re=C=CH[sub 2] with imines are the products Cp(CO)[sub 2]Re=CC(=C(H)Ph)C(H)PhN(R[prime]) (R[prime] = Me, Ph (15b)), which have an exocyclic double bond formed via an aldol-type condensation between the initial cycloadduct and excess imine. 35 refs., 10 figs., 8 tabs.

OSTI ID:
7267468
Journal Information:
Organometallics; (United States), Vol. 13:3; ISSN 0276-7333
Country of Publication:
United States
Language:
English