A domino approach to the enantioselective total syntheses of blennolide C and gonytolide C.
Chemistry
; 20(28): 8628-35, 2014 Jul 07.
Article
em En
| MEDLINE
| ID: mdl-24905446
ABSTRACT
The first enantioselective total syntheses of the tetrahydroxanthenone (-)-blennolideâ
C (ent-4) and related γ-lactonyl chromanone (-)-gonytolideâ
C (ent-3) are reported. Key to the syntheses is an enantioselective domino-Wacker/carbonylation/methoxylation reaction to set up the stereocentre at C-4a. Various chiral BOXAX ligands were investigated, including novel (S,S)-iBu-BOXAX, and allowed access to chromane 8 in an excellent enantioselectivity of 99 %. The second stereocentre at C-4 was established employing a diastereoselective Sharpless dihydroxylation. An extensive survey of (DHQ)- and (DHQD)-based ligands enabled the preparation of both the anti-isomer 14 a and the syn-isomer 14 b in very good to reasonable selectivities of 13.71 and 13.7, respectively. While 14 a was further converted to ent-3 and ent-4, 14 b was elaborated to syn-acid 25 and 2'-epi-gonytolideâ
C 28.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cromonas
/
Xantonas
Idioma:
En
Revista:
Chemistry
Assunto da revista:
QUIMICA
Ano de publicação:
2014
Tipo de documento:
Article