Synthesis of Medium Ring and Macrocyclic Acetylenic Lactones by the Ring Expansion of Oxabicycloalkenones
نویسنده
چکیده
Lactonas acetilênicas de tamanho médio e macrocíclico 15a-e [6-decin-9-olídeo (15a), 7-undecin-10-olídeo (15b), 8-dodecin-11-olídeo (15c), 12-hexadecin-15-olídeo (15d) e 5-decin-9olídeo (15e)] foram preparadas a partir de oxabiciclo-alquenonas 7a-d e 2, respectivamente, pela expansão de anel das tosil-hidrazonas 16a-e, efetuada pela reação com N-bromo-succinimida, sob condições rigorosamente controladas. A hidrogenação (Pd-C, H2) completa da ligação tripla forneceu lactonas racêmicas saturadas: 9-decanolídeo (foracantolídeo I, 6, de 15a e 15e), 10-undecanolídeo, 11-dodecanolídeo (di-hidro-recifeiolídeo) e 15-hexadecanolídeo. As tentativas de converter di-hidropironas 7a,d nas respectivas lactonas acetilênicas 15a,d, via cloro-hidrinas 8a,d e/ou clorocetolactonas 9a,d, foram apenas parcialmente bem sucedidas.
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