8 research outputs found
Acoplamientos arilo-alquino y alquino-alquino catalizados por Ni y Fe
Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Orgánica. Fecha de lectura: 21-06-201
Regio- and stereospecific copper-catalyzed substitution reaction of propargylic ammonium salts with aryl Grignard reagents
This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for
publication in Journal of the American Chemical Society, copyright © American Chemical Society after peer review. To access the final edited
and published work see http://doi.org/10.1021/jacs.7b05273We have developed a copper-catalyzed substitution reaction of propargylic ammonium salts with aryl Grignard reagents. The reaction is stereospecific and α-regioselective and proceeds with exceptional functional group tolerance. Conveniently, a stable, inexpensive, and commercially available copper salt is used and no added ligand is requiredWe thank the European Research Council (ERC-337776) and MINECO (CTQ2016-78779-R) for financial support. M.T. thanks MICINN for a RyC contrac
Copper-catalysed cross-coupling of alkyl Grignard reagents and propargylic ammonium salts: Stereospecific synthesis of allenes
Herein we describe a robust and practical method to prepare enantiomerically enriched trisubstituted allenes using alkyl Grignard reagents and bench stable propargylic ammonium salts. Excellent yields as well as regio- and stereoselectivities are observed. Our conditions provide a solution to the allene racemization, which has been a long-standing problem when using Grignard reagents
Photostability and Dynamic Helical Behavior in Chiral Poly(phenylacetylene)s with a Preferred Screw-Sense
Data Availability Statement
The data that support the findings of this study are available
in the supplementary material of this article.Acknowledgements
We thank Servicio de Microscopía Electrónica (RIAIDT,
USC). Financial support from AEI (PID2019-109733GBI00),
Ministerio de Ciencia e Innovación (PID2019-
107307RB-100 and PID2020-117605GB-100, PID2020-
113059GB-C21, PID2020-113059GB-C22). Xunta de Galicia
(ED431C 2018/30, ED431C 2021/40, Centro Singular de
Investigación de Galicia acreditación 2019–2022, ED431G
2019/03 and the European Regional Development Fund
(ERDF) is gratefully acknowledged. F.R.T. thanks Xunta de
Galicia for a predoctoral contract. We acknowledge CESGA
for computational time and we also thank Servicio de
Nanotecnología y Análisis de Superficies (CACTI-CINBIO,
UVigo).Helical polymers such as
poly(phenylacetylene)s (PPAs) are interesting materials
due to the possibility of tuning their helical scaffold
(sense and elongation) once they have been prepared
and by the presence of external stimuli. The main
limitation in the application of PPAs is their poor
photostability. These polymers degrade under visible
light exposure through a photochemical electrocyclization
process. In this work, it was demonstrated, through
a selected example, how the photochemical degradation
in PPAs is directly related to their dynamic helical
behavior. Thus, while PPAs with dynamic helical
structures show poor photostability under UV/Vis light
exposure, poly-(R)-1, bearing an enantiopure sulfoxide
group as pendant group and designed to have a quasistatic
helical behavior, shows a large photostability due
to the restricted conformational composition at the
polyene backbone, needed to orient the conjugated
double bonds prior to the photochemical electrocyclization
process and the subsequent degradation of the
material.AEI (PID2019-109733GBI00)Ministerio de Ciencia e Innovación (PID2019-
107307RB-100 and PID2020-117605GB-100, PID2020-
113059GB-C21, PID2020-113059GB-C22)Xunta de Galicia
(ED431C 2018/30, ED431C 2021/40, Centro Singular de
Investigación de Galicia acreditación 2019–2022, ED431G
2019/03 and the European Regional Development Fund
(ERDF
Copper-catalyzed diastereo- and enantioselective desymmetrization of cyclopropenes: Synthesis of cyclopropylboronates
This document is the accepted manuscript version of a Published Work that appeared in final form in Journal of American Chemical Society 136.45, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see DOI: 10.1021/ja510419zA novel Cu-catalyzed diastereo- and enantioselective desymmetrization of cyclopropenes to afford nonracemic cyclopropylboronates is described. Trapping the cyclopropylcopper intermediate with electrophilic amines allows for the synthesis of cyclopropylaminoboronic esters and demonstrates the potential of the approach for the synthesis of functionalized cyclopropanesWe thank the European Research Council (ERC-337776) and MINECO (CTQ2012-35957) for financial support. M. T. and A. P. thank MICINN for RyC and JdC contract
Turn-on Fluorescent Biosensors for Imaging Hypoxia-like Conditions in Living Cells
We present the synthesis, photophysical properties, and biological application of nontoxic 3-azo-conjugated BODIPY dyes as masked fluorescent biosensors of hypoxia-like conditions. The synthetic methodology is based on an operationally simple N=N bond-forming protocol, followed by a Suzuki coupling, that allows for a direct access to simple and underexplored 3-azo-substituted BODIPY. These dyes can turn on their emission properties under both chemical and biological reductive conditions, including bacterial and human azoreductases, which trigger the azo bond cleavage, leading to fluorescent 3-amino-BODIPY. We have also developed a practical enzymatic protocol, using an immobilized bacterial azoreductase that allows for the evaluation of these azo-based probes and can be used as a model for the less accessible and expensive human reductase NQO1. Quantum mechanical calculations uncover the restructuration of the topography of the S1 potential energy surface following the reduction of the azo moiety and rationalize the fluorescent quenching event through the mapping of an unprecedented pathway. Fluorescent microscopy experiments show that these azos can be used to visualize hypoxia-like conditions within living cellsThis article is dedicated to Professor M. Carmen Carreño on the
occasion of her retirement. We thank MINECO (grant
CTQ2017-85454-C2-2-P), MICINN (grant PID2020-
113059GB-C22), MCIU (grant PGC2018-094644-B-C21),
the Ramón y Cajal Program (grant RYC-2016-20489), the
Fundación La Caixa (grant no. LCF/BQ/DR19/11740024),
and the Comunidad Autónoma de Madrid (B2017/BMD-3867
RENIMCM) and co-financed by the European Structural and
investment fund for financial support. I.C. and F.R.-G. also
acknowledge the Red Española de Supercomputación, the
MareNostrum Supercomputer Center, and the Centro de
Computación Científica of the UAM (CCC-UAM) for the
generous allocation of computer time and for their technical
support. We thank the “Servicio de Microscopía óptica y
confocal CBMSO” facility for their assistance. We also thank
Prof. M. C. Carreño for her advice and helpful discussions
during the wor