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The first asymmetric total synthesis of Aspinolide B (1), a new 10-membered lactone discovered by chemical screening methods in the cultures of Aspergillus ochraceus, has been accomplished. The key steps included a selective Felkin-type addition of TMS-acetylene to aldehyde 3a and a Nozaki-Hiyama-Kishi coupling reaction to build the required 10-membered ring. This synthesis confirmed the absolute stereochemistry of aspinolide B, established through Helmchen's method and corrected its previously reported specific optical rotation.

An improved method to obtain naringin, a bitter flavored flavanone glicoside with proven biological activities, from grapefruit (Citrus x paradisi L.) peel waste is described. The proposed modification of the known process, which involves extraction with methanol and crystallization in water with the addition of dichloromethane, requires shorter processing time and reduced solvent volume. Due to the direct method employed, which did not require the 3-day air-drying stage, the hot extraction of fresh grapefruit albedo using methanol led to higher yields of naringin extract in half the time required. To evaluate the obtained naringin which possessed a wide range of pharmacological properties, it was subjected to chemical transformation into the flavone apigenin, an expensive and naturally-occurring flavonoid obtained in low yields.

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Recebido em 13/06/2019; aceito em 22/08/2019; publicado na web em 13/11/2019 COPPER: INDUSTRIAL PRODUCTION AND APPLICATIONS. This article is dedicated to element copper in honor to International Year of the Periodic Table celebrated in 2019. Copper is one of the oldest discovered chemical elements and manipulated by human being. In this sense, aspects about the element copper and its importance in different areas are described, from its mineral exploration through its processing and applications. Inorganic aspects such as structure of copper compounds and their main properties are presented as well the importance of this element in biological systems and organic reactions is explored, showing how essential copper is for life and society.

O uso da reação de Nozaki-Hiyama-Kishi para a formação de lactonas de 10 membros é descrita. A influência dos grupos de proteção em C4 e C5 sobre a estereoquímica do novo centro estereogênico formado em C7 foi investigada. A utilidade desta metodologia ficou demonstrada com a síntese total e estereosseletiva da (-)-decarestrictina D a partir do 1,3-propanodiol e poliidroxibutirato (PHB) em 13 etapas e 6,3% de rendimento total. The use of the intramolecular Nozaki-Hiyama-Kishi reaction to construct 10-membered lactones is described. The influence of the nature of the protecting groups at C4 and C5 on the stereochemistry of the newly formed stereogenic center at C7 was investigated. The utility of this methodology has been demonstrated in the stereoselective total synthesis of (-)-decarestrictine D from 1,3-propanediol and polyhydroxybutyrate (PHB) in 13 steps and 6.3% overall yield.