First Total Synthesis of Aspinolide B, a New Pentaketide Produced by Aspergillus ochraceus

Abstract

The first asymmetric total synthesis of Aspinolide B (1), a new 10-membered lactone discovered by chemical screening methods in the cultures of Aspergillus ochraceus, has been accomplished. The key steps included a selective Felkin-type addition of TMS-acetylene to aldehyde 3a and a Nozaki-Hiyama-Kishi coupling reaction to build the required 10-membered ring. This synthesis confirmed the absolute stereochemistry of aspinolide B, established through Helmchen's method and corrected its previously reported specific optical rotation.

Design and Synthesis of New Acid Cleavable Linkers for DNA Sequencing by Synthesis

“…[22][23][24][25][26] The known compound 5 was made in 22% overall yield as a mixture of diastereoisomers, and was used for the next step directly. Then, treatment of compound 5 with excess 2-bromoethanol and catalytic Amberlyst A-15 in dichloromethane under reflux delivered the desired ethers 6 in good yield.…”

Hypervalent iodine reagents in the total synthesis of natural products

“…In the latter case the reaction was performed in the presence of H 2 O (Scheme 10). 213,214 Water has also been used in other total syntheses using DMP in CH 2 Cl 2 , 97,121,122,215 because it accelerates the reaction. 13…”

Métodos de preparação de lactonas de anel médio

“…Pilli et al 59 também utilizaram a reação de Nozaki-HiyamaKishi na primeira síntese total do (-)-aspinolídeo, uma lactona natural isolada de culturas de Aspergillus ochraceus. Neste caso, o substrato inicial levou a uma mistura das lactonas de 10 membros, na proporção de 2:3, respectivamente (Esquema 26).…”