CICLOPROPANAÇÃO ASSIMÉTRICA INDUZIDA POR AUXILIARES QUIRAIS DERIVADOS DE CARBOIDRATOS E OS ESTUDOS DAS INTERAÇÕES AROMÁTICAS ENTRE A ANTRONA E DIMETOXINAFTALENOS

• Autor(a) principal: Leão, Raquel Ana Capela
• Data de Publicação: 2007
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal Fluminense (RIUFF)
• Texto Completo: https://app.uff.br/riuff/handle/1/21003
• topic: Ciclopropanação assimétrica; Carboidratos; Antrona; Dimetoxinaftalenos; Compostos aromáticos; Ligantes quirais (Química orgânico); Terpenos (Química orgânica); Dimetoxinaftaleno; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ORGANICA

The asymmetric cyclopropanation of alkenes using the hydroxysulfonamides 82-84 derived from terpenes, the bis(oxazoline) 88 and the carbohydrate derivatives MAR, DAG, DAF1, DAF2, DAGAL e DAAL was studied. The cylcopropanation reactions of cinnamyl alcohol with diethyl zinc catalyzed by the chiral lignds 82-84 were not effective, leading to the racemic alcohol 85. The reaction of styrene with ethyl diazoacetate catalyzed by Cu(I)-88 furnishing the mixture of trans-(1R, 2R)-87a and cis-(1R, 2R)-87a occurred in moderate diastereoselectivity, showing that 88 is somewhat efficient in this reaction. The reactions of styrene with the α-diazoacetates 86b-g derived from MAR, DAG, DAF1, DAF2, DAGAL e DAAL leading to mixtures of trans-87b-g and cis-87b-g depend on the catalyst employed, Rh(II) or Cu(I)-88; reactions in Cu(I)-88 gave better trans-87b-g: cis-87b-g ratios than those in Rh(II). In this regerds, the α-diazoacetate 86b derived from MAR was the most efficient system for the Cu(I)-88 catalyzed reaction with styrene and led to the ester trans-(1R, 2R)-87b in a trans-87b: cis-87b =95:5 and in 60% d. e. This result was explained by a preferential unlike attack of the styrene by the si face of the carbene-Cu(I) intermediate.