Studies on the total synthesis of lactonamycin: synthesis of the CDEF ring system.
A concise and efficient synthesis of the tetracyclic CDEF ring system of lactonamycin (1) is described. The key step involved the Lewis acid mediated, intramolecular Friedel-Crafts acylation of carboxylic acid 6 to produce the tetracyclic CDEF core structure of target 1. The synthesis of 6 was carried out using a high-yielding Negishi coupling of benzyl bromide 7 with triflate 8, which was accessible in 11 steps and 31% overall yield on a multigram scale starting from trihydroxy acid 9.
Wehlan
Hermut
H
Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, England.
Jezek
Eva
E
Lebrasseur
Nathalie
N
Pavé
Grégoire
G
Roulland
Emmanuel
E
White
Andrew J P
AJ
Burrows
Jeremy N
JN
Barrett
Anthony G M
AG
D007211:Indoles / Q000138:chemical synthesis; D009285:Naphthoquinones / Q000138:chemical synthesis
D007211:Indoles; D009285:Naphthoquinones; C102442:lactonamycin