AreneMoCO Complexes
Arene tricarbonyl molybdenum complexes are yellow, often crystalline compounds. They are weakly air-sensitive in the solid state and have to be stored under inert atmosphere and out of light. They are best purified by crystallization. In solution, they are unstable to air. The trait that has most hampered development of the use of arene Mo CO 3 complexes in organic synthesis, however, is the lability of the arene metal bond. Lewis basic solvents such as THF, DMF, DM-SO, acetone and acetonitrile...
Nucleophilic Substitution for Heteroatoms on Arene Ligands SNAR Reaction
The smooth replacement of a heteroatom usually halide via 9 and 10 requires reversible addition of the nucleophile, since the kinetic site of addition is usually at a position bearing a hydrogen substituent 11 in Scheme 2 charges omitted for clarity . Scheme 2 Nucleophile addition to metal-coordinated haloarene Scheme 2 Nucleophile addition to metal-coordinated haloarene The relative rates of each step depend critically on the nature of M and the nu-cleophile. More reactive nucleophiles and...
Cyclizations via Heteroatom Substitution for Halide
Intramolecular substitution for chloride or fluoride is particularly effective. Oxygen heterocycles with fused benzo rings are obtained from Cr CO 3 complexes of fluorobenzene with an o- hydroxyalkyl side chain 2 . Using a Cr CO 3 unit to direct a 2 2 cycloaddition to an imine, a stereoselective synthesis of a b-lactam was achieved 32 . From the o-dichlorobenzene complex, reaction with a dialkoxide can produce a cyclic bis-ether. This idea has been applied in the preparation of benzo-crown...