Cis- and trans-isoshinanolone from Dioncophyllum thollonii: absolute configuration of two `known', wide-spread natural products1Part 127 in the series `Acetogenic isoquinoline alkaloids'. For part 126, see Bringmann et al., submitted for publication (a).1
作者:Gerhard Bringmann、Miriam Münchbach、Kim Messer、Dagmar Koppler、Manuela Michel、Olaf Schupp、Matthias Wenzel、Adriaan M Louis
DOI:10.1016/s0031-9422(99)00080-1
日期:1999.7
From the rare West African liana, Dioncophyllum thollonii (Dioncophyllaceae), the known acetogenic tetralones, cis- and trans-isoshinanolone, were isolated. Exemplarily on this material, a new ruthenium-catalyzed oxidative degradation procedure, related to the well-established stereoanalysis of 1,3-dimethyltetrahydroisoquinolines lines, was ela berated. The method allo ws to unambiguously attribute the absolute configuration of these natural products, which likewise occur in several other plant species. For the rapid discrimination between the four possible stereoisomeric forms of isoshinanolone (i.e. the cis- and transdiastereomers and their enantiomers), an HPLC-analytical procedure on a chiral stationary phase has been developed. (C) 1999 Elsevier Science Ltd. All rights reserved.
Highly Efficient One-Pot Multienzyme Cascades for the Stereoselective Synthesis of Natural Naphthalenones
Herein, a biocatalytic cascade containing an ene-reductase (NostocER) and naphtholreductase (tetrahydroxynaphthalene or trihydroxynaphthalene reductase) of Magnaporthe grisea and NADPH is developed. The optimized multienzyme cascade is applied for the one-pot reduction of plumbagin to obtain biologically active cis-(3R,4R)-isoshinanolone, with drcis:trans 98:2 and >99% ee in 96% yield. Furthermore
在此,开发了包含稻瘟病菌和 NADPH的烯还原酶 (NostocER) 和萘酚还原酶 (四羟基萘或三羟基萘还原酶) 的生物催化级联反应。将优化后的多酶级联应用于一锅法还原白杨素,获得具有生物活性的顺式-(3 R ,4 R )-异紫荆醇酮,顺式:反式98:2 和 >99% ee,收率 96%。此外,还合成了具有优异立体选择性的天然 (+)-isosclerone、(+)-shinanolone、(-)-shinanolone 和 ( S )-4-hydroxy-3,4-dihydronaphthalen-1(2 H )-one和使用酶级联的高产率(71-89%)。NostocER-T的调查甲萘醌、铅黄素和 5-甲氧基甲萘醌的4 HNR 级联还原揭示了四羟基萘还原酶对这些底物的特异性。此外,动力学研究表明,与其他酶相比, NostocER 和 T 4 HNR 分别对铅黄素和二氢铅黄素具有较高的催化效率。