Sintese do triterpeno biciclico ent-a-polipodatetraeno : confirmação da configuração absoluta do produto natural

AUTOR(ES)
DATA DE PUBLICAÇÃO

1996

RESUMO

a-Polypodatetraene is a bicyclic triterpene isolated from Polypodium fauriei which the structure and absolute configuration were established by Ageta and collaborators. In the present work we developed the synthesis of the ent-a-polypodatetraene (1) starting from the copalic acid (2), in 9 steps with 3,2 % overall yield. The copalic acid (2) used in this work was isolated from commercial copaiba oil, which is one of the major components of the acidic fraction. Five routes of synthesis were developed to perform the side chain extension of copalic acid. The successful synthesis of ent-a-polypodatetraene 1 was achieved when the geranyl sulfonate 25 was alkylated with the bromine 24, which was prepared from copalic acid. The comparison of the optical rotation of the natural product ([a]D = +27,4°) with the synthetic product ([a]D = -18,9°), let us to confirm the absolute configuration of a-polypodatetraene enantiomer of 1. The difference between the absolute values of both optical rotations was attributed due to the copalic acid used in this work was 46%.

ASSUNTO(S)

terpenios essencias e oleos essenciais

ACESSO AO ARTIGO

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