Lipase B from Candida antarctica catalyzes the oxidative ring expansion of furfuryl alcohols using aqueous hydrogen peroxide to yield functionalized pyranones under mild conditions. The method further allows for the preparation of corresponding piperidinone derivatives by enzymatic rearrangement of N-protected furfurylamines.
来自南极念珠菌的脂肪酶 B 使用过氧化氢水溶液催化糠醇的氧化扩环,在温和条件下产生官能化的吡喃酮。该方法还允许通过N-保护的糠胺的酶促重排来制备相应的哌啶酮衍生物。
Cobalt-Catalyzed Oxygenation/Dearomatization of Furans
作者:Jonathan P. Oswald、K. A. Woerpel
DOI:10.1021/acs.joc.8b01183
日期:2018.8.17
The dearomatization of aromatic compounds using cobalt(II) acetylacetonate with triplet oxygen and triethylsilane converts furans, benzofurans, pyrroles, and thiophenes to a variety of products, including lactones, silyl peroxides, and ketones.
2-METHYL-3-HYDROXY-4H-pyran-4-one is prepared by contacting 1(2-furyl)-1-ethanol in aqueous solution with two equivalents of a halogen oxidant at room temperature and then heating until the hydrolysis of the formed 4-halo-dihydropyran intermediate is substantially complete. Other valuable related gamma-pyrones are prepared in analogous manner from appropriate alcohols.
<i>ansa</i>-Ruthenium(II) Complexes of R<sub>2</sub>NSO<sub>2</sub>DPEN-(CH<sub>2</sub>)<sub>n</sub>(η<sup>6</sup>-Aryl) Conjugate Ligands for Asymmetric Transfer Hydrogenation of Aryl Ketones
作者:Andrea Kišić、Michel Stephan、Barbara Mohar
DOI:10.1002/adsc.201500288
日期:2015.8.10
New 3rd generation designer ansa‐ruthenium(II) complexes featuring N,C‐alkylene‐tethered N,N‐dialkylsulfamoyl‐DPEN/η6‐arene ligands, exhibited good catalytic performance in the asymmetric transfer hydrogenation (ATH) of various classes of (het)aryl ketones in formic acid/triethylamine mixture. In particular, benzo‐fused cyclic ketones furnished 98 to >99.9% ee using a low catalyst loading.
Direct synthesis of ring-fused quinolines and pyridines catalyzed by <i>NN</i><sub><i>H</i></sub><i>Y</i>-ligated manganese complexes (Y = NR<sub>2</sub> or SR)
作者:Zheng Wang、Qing Lin、Ning Ma、Song Liu、Mingyang Han、Xiuli Yan、Qingbin Liu、Gregory A. Solan、Wen-Hua Sun
DOI:10.1039/d1cy01945g
日期:——
Four cationic manganese(I) complexes, [(fac-NNHN)Mn(CO)3]Br (Mn-1–Mn-3) and [(fac-NNHS)Mn(CO)3]Br (Mn-4) (where NNH is a 5,6,7,8-tetrahydro-8-quinolinamine moiety), have been synthesized and evaluated as catalysts for the direct synthesis of quinolines and pyridines by the reaction of a γ-amino alcohol with a ketone or secondary alcohol; NNHS-ligated Mn-4 proved the most effective of the four catalysts
四种阳离子锰( I )配合物,[( fac-NN H N )Mn(CO) 3 ]Br ( Mn-1 – Mn-3 ) 和 [( fac-NN H S )Mn(CO) 3 ]Br ( Mn -4 )(其中N H是 5,6,7,8-四氢-8-喹啉胺部分),已被合成并评估为通过 γ-氨基醇与酮或仲醇;NN H S -连接的Mn-4被证明是四种催化剂中最有效的。在催化剂负载量为 0.5-5.0 mol% 的情况下,反应进行得很好,并且可以耐受不同的官能团,如烷基、环烷基、烷氧基、氯化物和杂芳基。基于 DFT 计算和实验证据,提出了一种涉及无受体脱氢偶联 (ADC) 的机制。值得注意的是,这种基于锰的催化方案为广泛合成重要的取代单环、双环和三环N-杂环(包括 50 个喹啉和 26 个吡啶实例)提供了一条有前途的绿色环保途径,分离产率高达 93 %。