Oxidation of benzoins to benzils using bismuth(III) nitrate-copper(II) acetate

Síntese da fenitoína assistida por micro-ondas: proposta de aula prática para alunos de graduação

“…A oxidação da benzoína à sua respectiva alfa-dicetona, a benzila, é um método relativamente simples e amplamente descrito na literatura com o uso de diversos agentes oxidantes, como ácido nítrico, 24 solução de Fehling, 25 nitrato de tálio (III), 26 acetato de nitrato-cobre (II) e bismuto (III), 27 sais de cromo com alumina ácida, 28 dentre outros. Mais recentemente, foi relatada uma reação de oxidação para a benzoína empregando-se hidreto de sódio, 29 resultando em um rendimento elevado e sem o emprego de reagentes tóxicos, numa busca por um processo sintético mais limpo e seguro do ponto de vista ambiental.…”

Green chemistry-mediated synthesis of benzil by using nano-MgO

“…[11,12] The oxidation of benzoins is one of the most efficient and practical methods for the synthesis of benzils. In general, the oxidation of benzoins to benzils has been used, such as hallium nitrate, [13] ammonium nitrate-copper acetate, [14] bismuth nitrate-copper acetate, [15] and ferric nitrate. [16] The use of homogeneous reagents for the oxidation of benzoin limits their practical utilisations over heterogeneous catalysts in terms of product recovery, product selectivity and environmental concerns.…”

Oxidation of benzoins to benzils in the presence of porphyrin sensitizers by air and sunlight or visible light

“…Because of the above-mentioned properties of 1,2-diketones, various synthetic methods have been reported by different research groups, such as direct oxidation of a-hydroxyketones by using nitric acid [27], ammonium nitrate-copper(II) acetate [28], thallium(III) nitrate [29], iodoxybenzene [30], oxone-alumina [31], bismuth(III) nitrate-copper(II) acetate [32], iron(III) nitrate [33], tert-butyl hydroperoxide-titanium(IV) chloride [34], sodium hydride [35], and porphyrin [36]. 1,2-Diketones have been synthesized with different reagents, such as oxidation of 1,2-diols [37,38], oxidation of alkynes [39][40][41][42][43][44][45][46][47][48][49], oxidation of alkenes [50], oxidation of a-methylene ketones [51], rearrangement of a,b-epoxyketones [52][53][54], oxidation of vicinal dihaloalkenes [55], oxidation of epoxides [56], oxidation of 1,3-diols [57], and oxidation with molecular oxygen.…”