Reaction of 3,4-diphenyl- and 3-phenylisoxazole with strong bases (n-BuLi and LTMP, respectively) is a synthetically interesting reaction. In both cases C5-H abstraction and subsequent ring fragmentation is reported,1,2 with formation of inolate ions (useful starting materials, in turn, for the construction of other important systems: e.g., β-lactons,1,2 β-lactams3). We have extended the use of alkyllithiums to the reaction of 3-phenylisoxazole, discovering an unprecedented and more complex behaviour. Together with ring fragmentation and depending on the alkyllithium, nucleophilic addition of RLi and interaction of the «primary» products each other have in fact also been observed, with formation of alkylated enaminones and pyrimidines (Scheme).
Basic and Nucleophilic Action of Alkyllithiums in Reactions with 3-Phenylisoxazole
SCILIMATI, Antonio;VITALE, PAOLA
2004-01-01
Abstract
Reaction of 3,4-diphenyl- and 3-phenylisoxazole with strong bases (n-BuLi and LTMP, respectively) is a synthetically interesting reaction. In both cases C5-H abstraction and subsequent ring fragmentation is reported,1,2 with formation of inolate ions (useful starting materials, in turn, for the construction of other important systems: e.g., β-lactons,1,2 β-lactams3). We have extended the use of alkyllithiums to the reaction of 3-phenylisoxazole, discovering an unprecedented and more complex behaviour. Together with ring fragmentation and depending on the alkyllithium, nucleophilic addition of RLi and interaction of the «primary» products each other have in fact also been observed, with formation of alkylated enaminones and pyrimidines (Scheme).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
