Allylic Substitution Mediated by Water and Palladium: Unusual Role of a Palladium(II) Catalyst and ESI-MS Analysis

Autor:	Anna Pla-Quintana and, Anna Roglans, Jacques Muzart, Roser Pleixats, Jean Le Bras, and Françoise Hénin, Carole Chevrin
Rok vydání:	2004
Předmět:	Allylic rearrangement Electrospray ionization Organic Chemistry chemistry.chemical_element Carbocation Medicinal chemistry Catalysis Inorganic Chemistry Nucleophile chemistry Yield (chemistry) Organic chemistry Physical and Theoretical Chemistry Selectivity Palladium
Zdroj:	Organometallics. 23:4796-4799
ISSN:	1520-6041 0276-7333
DOI:	10.1021/om0495877
Popis:	Allylic substitution of PhCH(OAc)CHCHPh by CH2(COMe)2 in a basic MeOH/H2O mixture could be achieved in the absence of a palladium catalyst and lead to a mixture of PhCH(CH(COMe)2)CHCHPh and PhCH(OMe)CHCHPh in 40% and 55% yields, respectively. The process is induced by water, and nucleophilic attack addition occurred on a stabilized carbocation as the intermediate. Addition of a catalytic amount of PdCl2(CH3CN)2 did not accelerate the reaction but improved the selectivity, and PhCH(CH(COMe)2)CHCHPh was then obtained in 92% yield while PhCH(OMe)CHCHPh was observed in trace amounts. An ESI-MS analysis of the reaction mixture led us to assume that a palladium acetylacetonate complex is involved in the formation of PhCH(CH(COMe)2)CHCHPh.
Databáze:	OpenAIRE
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