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    7.1′,8.3′- and 7.3′,8.5′-Connected Bicyclo[3.2.1]octanoids and Oxabicyclo[3.2.2]nonane-Type Neolignans from Ocotea aciphylla: Structures and Absolute Configurations
    (ACS, 2024-02-23) Santos, Carlos Henrique Totini dos; Petrica, Edith Eunice Arthut; Batista, Andrea Nastri de Luca; Rodrigues, Edilene Delphino; Garcez, Walmir Silva; Albuquerque, Ana Carolina Ferreira de; Santos Jr, Fernando Martins dos; Batista Jr, Joao Marcos [UNIFESP]; Garcez, Fernanda Rodrigues; http://lattes.cnpq.br/4209224090500050
    The phytochemical investigation of the leaves and trunk bark of a specimen of Ocotea aciphylla collected in the southern portion of the Amazon forest led to the isolation of an oxabicyclo[3.2.2]nonane-type neolignan and 15 bicyclo[3.2.1]- octanoid neolignans, 14 of which are unreported compounds (2− 15), including one with an unusual oxidation pattern of the side chain at C-1′ and two rare 7.1′,8.3′-connected bicyclo[3.2.1]- octanoid derivatives. Their structures and relative configurations were determined by extensive spectrometric analysis based on 1D- and 2D-NMR spectroscopy and HRESIMS data, while their absolute configurations were unambiguously assigned using electronic and vibrational circular dichroism data assisted by density functional theory calculations. Additionally, known sesquiterpenes, phenylpropanoids, and phytosterols were also isolated
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    Resolution and absolute configuration of fargesin enantiomers
    (Wiley, 2024-11-06) Mestriner, Eloa R.; Lee, Eric Y. [UNIFESP]; Cunha, Camila L.; Sousa, Victor M.S. [UNIFESP]; Nascimento, Isabele R.; Batista Jr, Joao Marco [UNIFESP]; http://lattes.cnpq.br/4209224090500050
    Fargesin is an important bioactive furofuran lignan isolated from different plant species. Despite presenting potent biological activities, its stereochemical characterization has relied mostly on empirical correlations of optical rotation, an approach con- sidered risky that commonly leads to misassignments and error propagation. Additionally, the enantiomeric purity of fargesin isolates used for biological assays has not been previously investigated. Herein, we report the enantioresolution of a scalemic mixture of fargesin isolated from Aristolochia warmingii along with the first unambiguous determination of the absolute config- uration of each enantiomer by means of optical rotatory dispersion, as well as electronic and vibrational circular dichroism aided by quantum-chemical calculations.