Novel Organic Synthesis Using the Specific Reactivity of Transition Metal Carboxylate Complexes.

Development of novel and useful synthetic methods using a specific reactivity of transition metal carboxylate complexes was investigatated.(1)&lt；Pd(PPh_3)_4&gt；catalyzed a decarboxylative allylic alkylation of allylic acetates with&lt；beta&gt；-keto acids at room temperature to produce&lt；alpha&gt；-allylic ketones in good yields.(2)&lt；Pd(PPh_3)_4&gt；catalyzed a decific reactivity of transition metal carboxylate；-keto acids at room temperature to produce keto allylic alcohols in moderate to good yields.These two reactions with high regio-and stereoselectivity provide a useful method of the carbon-carbon bond formation involving carbonyl and/or hydroxyl functional groups and are characterized by the facile decarboxylation of palladium(&lt；II&gt；)&lt；beta&gt；-ketocaroxylate intermediates.It is highly interesting to note that these reactions proceed with a nucleophilic attack of enolate anions toward&lt；pi&gt；-allylpalladium(&lt；II&gt；)complexes in the presence of free carboxylic acids.(3)&lt；Pd(PPh_3)_4&gt；catalyzed a decarboxylative reduction of 1，3-diene monoepoxides with formic acid at room temperature to produce homoallylic alcohols in moderate of 1，3-diene monoepoxides with formic acid at room temperature to produce homoallylic alcohols in moderate proceed.The diynes showed a different reactivity from monoynes.The bicyclic&lt；alpha&gt；-pyrone formation may be assumed to involve cyclic organonickel carboxylate intermediates，the reductive elimination of which produces the bicyclic&lt；alpha&gt；-pyrones.Development of a nickel-catalyzed bicyclic&lt；alpha&gt；-pyrone formation may be expected on the basis of the present stoichiometric reaction。

Development of novel and useful synthetic methods using a specific reactivity of transition metal carboxylate complexes was investigated.(1) <Pd(PPh_3)_4> catalyzed a decarboxylative allylic alkylation of allylic acetates with <beta> -keto acids at room temperature to produce <alpha> -allylic ketones in good yields.(2) <Pd(PPh_3)_4> catalyzed a decarboxylative allylic alkylation of 1,3-diene monoepoxides with <beta> -keto acids at room temperature to produce keto allylic alcohols in moderate to good yields.These two reactions with high regio- and stereoselectivity provide a useful method of the carbon-carbon bond formation involving carbonyl and/or hydroxyl functional groups and are characterized by the facile decarboxylation of palladium( <II> ) <beta> -ketocarboxylate intermediates. It is highly interesting to note that these reactions proceed with a nucleophilic attack of enolate anions toward <pi> -allylpalladium( <II> ) complexes in the presence of free carboxylic acids.(3) <Pd(PPh_3)_4> catalyzed a decarboxylative reduction of 1,3-diene monoepoxides with formic acid at room temperature to produce homoallylic alcohols in moderate yields.(4) An equimolar amount of Ni(O)-tertiary phosphine complexes effected a cycloaddition of diynes and carbon dioxide at 130 ゜C to produce bicyclic <alpha> -pyrones. The diynes showed a different reactivity from monoynes. The bicyclic <alpha> -pyrone formation may be assumed to involve cyclic organonickel carboxylate intermediates, the reductive elimination of which produces the bicyclic <alpha> -pyrones. Development of a nickel-catalyzed bicyclic <alpha> -pyrone formation may be expected on the basis of the present stoichiometric reaction.