by a biomimetic and chemoenzymatic approach using NADPH‐dependent polyhydroxyanthracence reductase (PHAR) from Cochliobolus lunatus followed by Pb(OAc)4 oxidation is reported. Subsequent dimerization through a hetero‐Diels–Alderreaction of the dihydroemodin and dihydrolunatin resulted in (−)‐flavoskyrin (68 %) and (−)‐lunaskyrin (62 %), respectively. Pyridine treatment of (−)‐flavoskyrin and (−)‐lunaskyrin
We report a first synthesis of racemic dihydroanthracenones through regioselective reduction of hydroanthraquinones using NaBH4 in water. Their use confirms the enantiopurity of chiral dihydroanthracenones synthesized chemoenzymatically and of the bisanthraquinone analogues.
oxidoreductase from Talaromyces islandicus WF-38-12 has been identified through genome analysis. It has been shown to catalyze a regio- and stereoselective reduction of anthrols (formed in situ by the reduction of anthraquinones in the presence of Na2S2O4) to (R)-dihydroanthracenones, with high enantiomeric excess (>99%). The implications of results on the biosynthesis of deoxygenated (bis)anthraquinones and
通过基因组分析已经鉴定了来自岛形Talaromyces islandicus WF-38-12的NADPH依赖性氧化还原酶。已显示其催化对映异构和立体选择性的蒽还原反应(对映异构体过量(> 99%))(在Na 2 S 2 O 4存在下通过蒽醌还原原位形成)变为(R)-二氢蒽酮。。讨论了结果对脱氧(双)蒽醌和改性(双)蒽醌的生物合成的影响。
Promiscuity of an unrelated anthrol reductase of <i>Talaromyces islandicus</i> WF-38-12
Synthesis of (−)-Flavoskyrins by Catalyst-Free Oxidation of (<i>R</i>)-Configured Dihydroanthracenones in Aqueous Media and Its (Bio)synthetic Implications
作者:Amit Mondal、Arijit De、Syed Masood Husain
DOI:10.1021/acs.orglett.0c03121
日期:2020.11.6
A catalyst-free method for the synthesis of dimeric (-)-flavoskyrins has been developed. It involves the autoxidation of chemoenzymatically synthesized (R)-configured dihydroanthracenones in the presence of molecular oxygen in buffer of pH 6.0 followed by spontaneous [4 + 2] cycloaddition in stereocontrolled exo-anti fashion to form (-)-flavoskyrins. The method is applied to obtain several homo- as well as heterodimerized flavoskyrins (nine examples) in 27-72% yield and implies the involvement of a similar pathway in the (bio)synthesis of modified bisanthraquinones and their analogues.