Botrytis sp., isolated from the inner bark of the Pacific yew, Taxus brevifolia, was shown to produce ramulosin (1), 6-hydroxyramulosin (2), and the new compound 8-dihydroramulosin (3). The structure of dihydroramulosin was deduced from the NMR spectra and confirmed by chemical conversion from ramulosin.
Chiral synthesis of (R)-( -)-mellein and (3R,4aS)-( + )-ramulosin
作者:Kenji Mori、Ashok K. Gupta
DOI:10.1016/s0040-4020(01)96780-8
日期:——
By employing an intramolecular Diels-Alder reaction as the key-step, (R)-(—)-mellein 1a (a metabolite of Aspergittus melleus) and (3R,4aS)-( +)-ramulosin 2 (a metabolite of Pestalotia ramulosa) were synthesised from ethyl (R)-3-hydroxybutanoate 3a.
(−)-Mellein, (+)-ramulosin, (−)-O-methylmellein, (−)-6-hydroxymellein, (−)-6-methoxymellein, and (+)-6-hydroxyramulosin were synthesized as optically active forms using one-pot esterification–Michael addition–aldol reaction of δ-hydroxy-α,β-unsaturated aldehyde and diketene as a key step.
合成了(-)-Mellein,(+)-ramusosin,(-)- O -methylmellein,(-)-6-hydroxymellein,(-)-6-methoxymethoxyle,和(+)-6-hydroxyramulosin。使用一锅酯化-迈克尔加成-δ-羟基-α,β-不饱和醛和双烯酮的醛醇缩合反应是关键步骤。
Diastereoselective 1,4-addition of various nucleophiles to 5-trimethylsilyl-2-cyclohexenone: synthesis of (+)-ramulosin