RESUMO
(+)-Clusianone, an exo-type B PPAP with reported anti-HIV and chemoprotective activities, was synthesized in eleven steps with 97% ee starting from acetylacetone. An enantioselective decarboxylative Tsuji-Trost-allylation and a Ru-catalyzed ring-closing metathesis-decarboxylative allylation were used to control both diastereo- and enantioselectivity.
Assuntos
Benzofenonas/síntese química , Benzoquinonas/síntese química , Fármacos Anti-HIV/síntese química , Fármacos Anti-HIV/química , Antineoplásicos/síntese química , Antineoplásicos/química , Benzofenonas/química , Benzoquinonas/química , Catálise , Cristalografia por Raios X , Conformação Molecular , Rutênio/química , EstereoisomerismoRESUMO
Polyprenylated polycyclic acylphloroglucinols (PPAP) are a constantly growing class of natural products that exhibit a common bicyclo[3.3.1]nonatrione core and consist of currently more than 200 members. A subclassification among the various natural products of this class includes the position of the exocyclic acyl group, the prenylation grade of the core, and the relative configuration at C-7 within the core. About 10% of the reported structures, however, possess an additional chiral center at C-6. Herein we describe a straightforward access to guttiferone A and epi-guttiferone A, in which full control of stereoselectivity is achieved via conformational control, and a strict separation of framework decorating from framework constructing operations sets the stage for a short 13-step synthesis.
