A comparison of the benzylic and the allylic group as a donor in the formal [4+2] cycloaddition to tetrahydropyrans using donor-acceptor cyclobutanes
摘要:
The allyl group was shown to be preferred over the benzyl group as a donor in the formal [4+2]-cyclo-addition reaction between a donor-acceptor cyclobutane and various aldehydes to give tetrahydropyrans. (C) 2017 Elsevier Ltd. All rights reserved.
DOI:
10.1016/j.tetlet.2017.06.046
作为产物:
描述:
肉桂醛 、 丙二酸二甲酯 在
lithium salt of proline 作用下,
以
甲醇 为溶剂,
反应 1.0h,
以77%的产率得到dimethyl 2-(3-oxo-1-phenylpropyl)malonate
参考文献:
名称:
The Michael addition of dimethyl malonate to α,β-unsaturated aldehydes catalysed by proline lithium salt
Polystyrene-Supported Diarylprolinol Ethers as Highly Efficient Organocatalysts for Michael-Type Reactions
作者:Esther Alza、Sonia Sayalero、Pinar Kasaplar、Diana Almaşi、Miquel A. Pericàs
DOI:10.1002/chem.201101730
日期:2011.10.4
addition of aldehydes to nitroolefins and of malonates or nitromethane to α,β‐unsaturated aldehydes. The combination of the catalytic unit, the triazole linker, and the polymeric matrix provides unprecedented substrate selectivity, in favor of linear, short‐chain aldehydes, when the organocatalyzed reaction proceeds by an enamine mechanism. High versatility is noted in reactions that proceed via an iminium
A versatile and highly stereoselective synthetic route to functionalized bi- and tricyclic lactams (up to > 20:1 dr and 99 % ee) in one pot from simple starting materials (allylic alcohols, enal ...
一种多功能且高度立体选择性的合成路线,可在一个锅中从简单的起始材料(烯丙醇、烯醛)制备功能化的双环和三环内酰胺(高达 > 20:1 dr 和 99 % ee)。
A Recyclable Chiral 2‐(Triphenylmethyl)pyrrolidine Organocatalyst Anchored to [60]Fullerene
作者:Cristian Rosso、Marco G. Emma、Ada Martinelli、Marco Lombardo、Arianna Quintavalla、Claudio Trombini、Zois Syrgiannis、Maurizio Prato
DOI:10.1002/adsc.201900009
日期:2019.6.18
[60]fullerene via click chemistry provides a highlyefficient supported enantioselectiveorganocatalyst, which was successfully exploited in a Michaeladdition of malonates to cinnamaldehydes, via iminium ion activation. The supported organocatalyst was recycled up to six times, with only a moderate decrease in terms of activity and with no loss in enantioselectivity.
An enantio- and diastereoselective approach to indoloquinolizidines in continuous flow
作者:Moreshwar B. Chaudhari、Prachi Gupta、Patricia Llanes、Leijie Zhou、Nicola Zanda、Miquel A. Pericàs
DOI:10.1039/d2ob01462a
日期:——
short synthesis of indoloquinolizidines. Using this approach, a highly enantioselective, solvent-free and rapid conjugate addition of dimethyl malonate to a diverse family of cinnamaldehydes in continuous flow, allowing the preparation of relevant oxodiesters in multigram amounts has been developed. The obtained Michael adducts have been used to complete an expedient diastereoselective synthesis of indoloquinolizidine
Distribution of Catalytic Species as an Indicator To Overcome Reproducibility Problems
作者:Xavier Companyó、Jordi Burés
DOI:10.1021/jacs.7b05045
日期:2017.6.28
Irreproducibility is a common issue in catalysis. The ordinary way to minimize it is by ensuring enhanced control over the factors that affect the reaction. When control is insufficient, some parameters can be used as indicators of the reaction performance. Herein we describe the use of the distribution of catalytic species as an indicator to map, track, and fine-tune the performance of catalytic reactions. This indicator is very sensitive and presents a quick response to variations in the reaction conditions. We have applied this new strategy to the conjugate addition of C-nucleophiles to enals via iminium intermediates, consistently achieving maximum turnover frequencies (TOF) regardless of the quality of the starting materials used. In addition, the present method has allowed us to efficiently reduce the catalyst loading to as little as 0.1 mol %, the lowest one described for this kind of reaction.