Copper-catalyzed desymmetrization of prochiral 4,4-disubstituted cyclopentenes via a site-selective allylic oxidation: a concise total synthesis of untenone A

2019 ◽  
Vol 55 (82) ◽  
pp. 12368-12371
Author(s):  
Qingwen Gui ◽  
JuanJuan Wang ◽  
Sean Ng ◽  
Anja Dancevic ◽  
Timothy B. Wright ◽  
...  

The desymmetrization of prochiral 4,4-disubstituted cyclopentenes via a site-selective copper-catalyzed allylic oxidation is described.

2018 ◽  
Vol 54 (8) ◽  
pp. 912-915 ◽  
Author(s):  
Ziyun Yuan ◽  
Xiaojun Hu ◽  
Hao Zhang ◽  
Lin Liu ◽  
Peng Chen ◽  
...  

The strategy developed for the first total synthesis of highly oxygenated natural product conosilane A involving double manipulation of allylic C(sp3)–H functionalization renders the power of C–H functionalization in organic syntheses.


1996 ◽  
Vol 451 ◽  
Author(s):  
D. Lincot ◽  
M. J. Furlong ◽  
M. Froment ◽  
R. Cortes ◽  
M. C. Bernard

ABSTRACTChalcogenide semiconductors have been deposited epitaxially from aqueous solutions either chemically or electrochemically at growth rates of up to 0.7 μmhr−1. After recalling the basic principles of these deposition processes, results are presented concerning chemically deposited CdS on InP, GaP and CuInSe2 substrates, electrodeposited CdTe on InP, and CdSAnP heterostructures. Characterisation of these structures by RHEED, TEM, HRTEM, and glazing angle X ray diffraction allows to analyse the effects of substrate orientation, polarity, lattice match plus the influence of temperature on epitaxial growth. These results are discussed in terms of self organisation and a site selective growth mechanisms due to the free enegy of formation of each compound.


2021 ◽  
Vol 6 (43) ◽  
pp. 12032-12035
Author(s):  
Jinjing Qin ◽  
Zhenhua Li ◽  
Yingyan Cao ◽  
Yuanyuan Xie ◽  
Weike Su
Keyword(s):  
A Site ◽  

2021 ◽  
Author(s):  
Viktoriia Postupalenko ◽  
Léo Marx ◽  
David Viertl ◽  
Natalia Gasilova ◽  
Mathilde Plantin ◽  
...  

2021 ◽  
Author(s):  
Sourav Sekhar Bera ◽  
Srishti Ballabh Bahukhandi ◽  
Claire Empel ◽  
Rene M Koenigs

A site-selective direct arylation reaction of carbazole and other N-heterocycles with diazo-naphthalen-2(1H)-ones has been developed. While Au(I)-NHC catalysts lead to selective C3-arylation, palladium acetate allows for selective N-H arylation, displaying...


Synlett ◽  
2018 ◽  
Vol 29 (09) ◽  
pp. 1203-1206 ◽  
Author(s):  
Hyoungsu Kim ◽  
Hosam Choi ◽  
Kiyoun Lee

A concise total synthesis of (±)-mesembrine has been successfully accomplished in seven steps and 24% overall yield from commercially available 3-ethoxy-2-cyclohexen-1-one. Central to the assembly of the skeleton of mesembrine are a Johnson–Claisen rearrangement for the formation of the benzylic quaternary stereocenter and direct allylic oxidation to generate the substrate for the amidation/transannular aza-conjugate addition reaction.


2009 ◽  
Vol 49 (1) ◽  
pp. 144-147 ◽  
Author(s):  
Jun Terao ◽  
Masahiro Tomita ◽  
Surya Prakash Singh ◽  
Nobuaki Kambe

2018 ◽  
Author(s):  
Martin A. Fascione ◽  
Richard J. Spears ◽  
Robin L. Brabham ◽  
Darshita Budhadev ◽  
Tessa Keenan ◽  
...  

The bioconjugation of proteins with small molecules has proved an invaluable strategy for probing and perturbing dynamic biological mechanisms. The general use of chemical methods for the functionalisation of proteins remains limited however by the frequent requirement for complicated reaction partners to be present in large excess, and harsh reaction conditions which are incompatible with many protein scaffolds. Herein we describe a site-selective organocatalyst-mediated protein aldol ligation (OPAL) that affords stable carbon-carbon linked bioconjugates at neutral pH under biocompatible conditions. OPAL enables rapid chemical modification of proteins within an hour using simple aldehyde probes in minimal excess, and is utilised here in the selective affinity tagging of proteins in cell lysate. Furthermore we demonstrate that the b-hydroxy aldehyde product of the OPAL can be functionalised a second time at neutral pH in a subsequent organocatalyst-mediated oxime ligation. This tandem strategy is showcased in the ‘chemical mimicry’ of a previously inaccessible natural dual post-translationally modified protein integral to the pathogenesis of the neglected tropical disease Leishmaniasis. <br>


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