Total synthesis of (+)-crocacins "C" and"D": synthesis of the 6,6-spiroketals / Sintese total das (+)-crocacinas C e D : sintese dos fragmentos 6,6-espirocetal das espirofunginas A e B

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Chapter 1 describes the asymmetric total synthesis of (+)-crocacin C (1.3) and D (1.4). The convergent total synthesis of (1.3) relies on the use of a regio- and stereoselective epoxidation of an allylic alcohol with m-CPBA followed by epoxide opening with Me2CuCNLi2 and a Stille cross-coupling between (E)-vinyl stannane (1.111) and (E)-vinyl iodide (+)-(1.112) to stabilish the (E,E)-dienamide moiety. The total synthesis of (+)-crocacin D (1.4) uses a mild and efficient copper-catalyzed coupling reaction between (+)-crocacin C (1.3) and Z-vinyl iodide (1.160) to establish the challenging (Z)-enamide function. Chapter 2 describes our initial efforts toward the total synthesis of the antifungal antibiotics spirofungins A and B. A short and efficient synthesis of the C9-C20 6,6-spiroketal fragments of both compounds is described. This asymmetric approach uses a very efficient alkylation of a lithiated N,N-dimethylhydrazone followed by spiroketal formation under acidic conditions.

ASSUNTO(S)

fungal antigens antibioticos policetidicos (z)enamides antigenos de fungos poliketide antibiotics spiroketals (z)enamidas espirocetais

ACESSO AO ARTIGO

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