نتایج جستجو برای: organocatalysis

تعداد نتایج: 465  

Journal: :Science 2007
Teresa D Beeson Anthony Mastracchio Jun-Bae Hong Kate Ashton David W C Macmillan

The asymmetric alpha-addition of relatively nonpolar hydrocarbon substrates, such as allyl and aryl groups, to aldehydes and ketones remains a largely unsolved problem in organic synthesis, despite the wide potential utility of direct routes to such products. We reasoned that well-established chiral amine catalysis, which activates aldehydes toward electrophile addition by enamine formation, co...

2014
Yumei Xiao Zhanhu Sun Hongchao Guo Ohyun Kwon

This review discusses the tertiary phosphines possessing various chiral skeletons that have been used in asymmetric nucleophilic organocatalytic reactions, including annulations of allenes, alkynes, and Morita-Baylis-Hillman (MBH) acetates, carbonates, and ketenes with activated alkenes and imines, allylic substitutions of MBH acetates and carbonates, Michael additions, γ-umpolung additions, an...

Journal: :Molecules 2016
Xufeng Hou Zhenzhong Jing Xiangbin Bai Zhiyong Jiang

Reported is a rationally-designed one-pot sequential strategy that allows homoallylic alcohols to be employed in a catalytic, asymmetric, direct vinylogous aldol reaction with a series of activated acyclic ketones, including trifluoromethyl ketones, γ-ketoesters, and α-keto phosphonates, in high yields (up to 95%) with excellent regio- and enantio-selectivity (up to 99% ee). This modular combin...

Journal: :Organic letters 2014
Yu Du Yuhuang Wang Xin Li Yaling Shao Guohui Li Richard D Webster Yonggui Robin Chi

An unprecedented N-heterocyclic carbene catalytic reductive β,β-carbon coupling of α,β-nitroalkenes, by using an organic substrate to mimic the one-electron oxidation role of the pyruvate ferredoxin oxidoreductase (PFOR) in living systems, has been developed. The reaction goes through a radical anion intermediate generated under a catalytic redox process. For the first time, the presence of rad...

Journal: :Molecules 2017
Diego A Alonso Alejandro Baeza Rafael Chinchilla Cecilia Gómez Gabriela Guillena Isidro M Pastor Diego J Ramón

The asymmetric conjugate addition of carbon and heteroatom nucleophiles to nitroalkenes is a very interesting tool for the construction of highly functionalized synthetic building blocks. Thanks to the rapid development of asymmetric organocatalysis, significant progress has been made during the last years in achieving efficiently this process, concerning chiral organocatalysts, substrates and ...

Journal: :Progress in the chemistry of organic natural products 2012
Mario Waser

Now welcome, the most inspiring book today from a very professional writer in the world, asymmetric organocatalysis in natural product syntheses. This is the book that many people in the world waiting for to publish. After the announced of this book, the book lovers are really curious to see how this book is actually. Are you one of them? That's very proper. You may not be regret now to seek fo...

2014
Jack A. Terrett Michael D. Clift David W. C. MacMillan

Direct β-alkylation of saturated aldehydes has been accomplished by synergistically combining photoredox catalysis and organocatalysis. Photon-induced enamine oxidation provides an activated β-enaminyl radical intermediate, which readily combines with a wide range of Michael acceptors to produce β-alkyl aldehydes in a highly efficient manner. Furthermore, this redox-neutral, atom-economical C-H...

Journal: :Journal of the American Chemical Society 2013
Filip R Petronijević Manuel Nappi David W C MacMillan

The direct β-coupling of cyclic ketones with aryl ketones has been achieved via the synergistic combination of photoredox catalysis and organocatalysis. Diaryl oxymethyl or aryl-alkyl oxymethyl radicals, transiently generated via single-electron reduction of ketone precursors, readily merge with β-enaminyl radical species, generated by photon-induced enamine oxidation, to produce γ-hydroxyketon...

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