New Isopropylmaltol - Ti Synthesis and its Use as a Catalyst for Olefin Polymerization
摘要:
This report describes a new synthesis of isopropylmaltol from furfural. This organic compound was used as ligand to obtain a new complex, the dichlorobis-(3-hydroxy-2-isopropyl-4-pyrone) titanium(IV). H-1 nuclear magnetic ressonance, elemental analysis and UV-Vis analysis confirm the complex formation. This complex was investigated in ethylene polymerization using methylaluminoxane (MAO) as cocatalyst. The catalytic activity was low, however, there were obtained very high molecular weight polyethylenes, which are interesting for various special applications.
cytotoxic natural products that show promising selective inhibitory activity against PTP1B. Here the first asymmetric total syntheses of (+)-penostatins A and C are reported. Our strategy features (i) a new method for the synthesis of 6-alkyl-3-hydroxy-2-pyrones, (ii) a cascade involving the intramolecular Diels–Alder reaction of 2-pyrone and a retro-hetero-Diels–Alder (decarboxylation) reaction, (iii)
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。
Palladium‐Catalyzed Regioselective and Diastereoselective
<i>C</i>
‐Glycosylation by Allyl‐Allyl Coupling
作者:Junhao Li、Nan Zheng、Xuelun Duan、Rui Li、Wangze Song
DOI:10.1002/adsc.202001136
日期:2021.2.2
A Pd‐catalyzed C‐glycosylation reaction was developed by allyl‐allyl coupling process using Achmatowicz rearrangement products as donors and methylcoumarins as acceptors under mild conditions. This method featured regio‐ and diastereoselectivities, stereodivergent synthesis of C‐glycosides. The glycosyl donors with controlled stereodiversity and glycosyl acceptors with fluorescent performace further
A solvent-free catalytic protocol for the Achmatowicz rearrangement
作者:Guodong Zhao、Rongbiao Tong
DOI:10.1039/c8gc03030h
日期:——
Reported here is the development of an environmentally friendly catalytic (KBr/oxone) and solvent-free protocol for the Achmatowiczrearrangement (AchR). Different from all previous methods is that the use of chromatographic alumina (Al2O3) allows AchR to proceed smoothly in the absence of any organic solvent and therefore considerably facilitates the subsequent workup and purification with minimal
这里报道的是针对Achmatowicz重排(AchR)的环保型催化(KBr / oxone)和无溶剂方案的开发。与所有以前的方法不同的是,使用色谱氧化铝(Al 2 O 3)可使AchR在不存在任何有机溶剂的情况下顺利进行,因此可极大地促进后续的后处理和纯化,并且对环境的影响最小。重要的是,该协议允许按比例放大(从毫克到克),回收Al 2 O 3以及与其他反应按一锅顺序方式进行整合。
Synthesis of sex pheromone 3,5-cis-dimethyl-6-trans-isopropyl-3,4,5,6-tetrahydropyran-2-one
作者:Satya V.N. Raju、Bipin Pandey
DOI:10.1016/s0040-4039(00)76240-x
日期:1994.2
An expeditious stereoselectivesynthesis of sexpheromone (±)3,5-cis-dimethyl-6-trans-isopropyl-3,4,5,6-tetrahydropyran-2-one of larval parasitoid M. grandii, from readily available isobutyraldehyde and furan is described.