Metals, reagents for

Mixed-Metal Systems. Mixed-metal systems, where a zirconium alkyl is formed and the alkyl group transferred to another metal, are a new apphcation of the hydrozirconation reaction. These systems offer the advantages of the easy formation of the Zr—alkyl as well as the versatiUty of alkyl—metal reagents. For example, Cp2ZrRCl (R = alkyl or alkenyl) reacts with AICI3 to give an Al—alkyl species which may then be acylated with... 

Richmond TG (1999) Metal Reagents for Activation and Functionalization of Carbon-Fluorine Bonds. 3 243-269... 

Ribaudo F, van Leeuwen PWNM, Reek JNH (2006) Supramolecular Dendritic Catalysis Noncovalent Catalyst Anchoring to Fimctionalized Dendrimers. 20 39-59 Richmond TG (1999) Metal Reagents for Activation and Functionalization of Carbon-Fluorine Bonds. 3 243-269... 

Catalytic allylic alkylation with Pd is one of the most powerfiil techniques to come out of the development of organotransition metal reagents for organic synthesis. Especially powerfiil is the versatility in the reactants a wide range of allyl species with electronegative allylic substituents and essentially every type of nucleophile. Allylic alkylation using metals other than Pd are known but have been less commonly applied to organic synthesis. 

The alkali metal hydrides NaH and KH are also effective as metalating reagents for hydrosilane and disilane to give trialkylsilyl anions in an aprotic solvent such as THE, DME, or HMPA 8) (Scheme 4) (for the mechanism, see Section III-A-2). The reaction of disilane with 2 equivalents of metal hydride converts both silyl groups into silyl anions in two steps, in contrast to the reaction with MeOM described earlier. 

A potentially useful chemoselective dissolving metal reagent for the reduction of aromatic ketones in the presence of other functional groups is the combination Zn-DMSO and aqueous potassium hydroxide. In three examples (benzophenone, fluorenone and 4-benzoylpyridine), the yields of secondary alcohols were over 90%. Two other ketones (xanthone and thioxanthone) gave mixtures of alcohol and the hydrocarbon obtained by hydrogenolysis of a carbon-oxygen bond. ... 

Divalent metal halides readily undergo salt elimination reactions with a diverse array of metallated reagents. For example, SnC undergoes such a reaction with a diiminophosphinate to form a four-coordinate complex in low yield (16%) ... 

The reactions are carried out in the presence of a base, preferably a metallating reagent for the amine. 

Transition Metal Reagents for Aromatic C-F Bond Activation. . . 250... 

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