RESUMO
Anionic annulations of 3-nucleofugal phthalides with α-alkyl(aryl)acrylates involving a demethoxycarbonylation provide a succinct synthesis of vitamin K and related naphthoquinones. Also reported is a new cascade reaction stemming from a Cope-retro-Wittig rearrangement. This cascade leads to direct formation of 1-hydroxy-4-prenyloxynaphthalene-2-carboxylates from the corresponding α-prenyl acrylate acceptors.
Assuntos
Naftoquinonas/síntese química , Vitamina K/análogos & derivados , Vitamina K/síntese química , Acrilatos/química , Ácidos Carboxílicos/síntese química , Ácidos Carboxílicos/química , Técnicas de Química Combinatória , Estrutura Molecular , Naftoquinonas/química , Estereoisomerismo , Vitamina K/químicaRESUMO
The annulation of phthalides with α-alkyl/arylacrylates in the presence of LDA/LHMDS is shown to directly give alkyl/aryl-1-naphthols. The method involving a novel dealkoxycarbonylation obviates the regiochemical issues in the synthesis of polysubstituted naphthalenes, and it forms the key step in a three-step total synthesis of arnottin I, a naphthobenzopyranone natural product.