6 research outputs found
Regioselective and Enantioselective Intermolecular Buchner Ring Expansions in Flow
The first example of a regioselective
and enantioselective intermolecular
Buchner ring expansion is reported using continuous flow. The practicality
and scope of the reaction are greatly improved under flow conditions.
Reactions of ethyl diazoacetate with symmetric and nonsymmetric arenes
afford cycloheptatrienes in good yield and excellent regioselectivity.
The first example of an asymmetric intermolecular Buchner reaction
is demonstrated with disubstituted diazo esters in good to excellent
enantioselectivity. The asymmetric reactions proceed with absolute
regioselectivity to afford cycloheptatrienes with an all-carbon quaternary
center
Synthesis of Azaphilone-Based Chemical Libraries
The synthesis of azaphilone scaffolds that have been
further diversified
by cross coupling acylation and amine addition is reported. Methodology
development also led to novel modifications including C5 acetoxylation
and condensations producing isoquinolin-6(7H) structures. Overall,
the library synthesis afforded three azaphilone sublibraries, including
vinylogous pyridones which project diversity elements in four sectors
of the azaphilone core
Redesign of a Pyrylium Photoredox Catalyst and Its Application to the Generation of Carbonyl Ylides
We
report the exploration into photoredox generation of carbonyl
ylides from benzylic epoxides using newly designed 4-mesityl-2,6-diphenylpyrylium
tetrafluoroborate (MDPT) and 4-mesityl-2,6-di-<i>p</i>-tolylpyrylium
tetrafluoroborate (MD(<i>p</i>-tolyl)PT) catalysts. These
catalysts are excited at visible wavelengths, are highly robust, and
exhibit some of the highest oxidation potentials reported. Their utility
was demonstrated in the mild and efficient generation of carbonyl
ylides from benzylic epoxides that otherwise could not be carried
out by current common photoredox catalysts
Synthesis and Reactivity of Bicyclo[3.2.1]octanoid-Derived Cyclopropanes
Photochemical oxa-di-π-methane rearrangement of
bicyclo[3.2.1]octanoid
scaffolds affords multifunctional, donor–acceptor cyclopropanes.
A related photochemical reaction of an iminium ether substrate uncovered
an unprecedented aza-di-π-methane
rearrangement of a β,γ-unsaturated iminium. Donor–acceptor
cyclopropanes have been evaluated as substrates for reactions generating
several new chemotypes
Multidimensional Reaction Screening for Photochemical Transformations as a Tool for Discovering New Chemotypes
We
have developed an automated photochemical microfluidics platform
that integrates a 1 kW high-pressure Hg vapor lamp and allows for
analytical pulse flow or preparative continuous flow reactions. Herein,
we will discuss the use of this platform toward the discovery of new
chemotypes through multidimensional reaction screening. We will highlight
the ability to discretely control wavelengths with optical filters,
allowing for control of reaction outcomes
Development of a Potent and Selective HDAC8 Inhibitor
A novel,
isoform-selective inhibitor of histone deacetylase 8 (HDAC8)
has been discovered by the repurposing of a diverse compound collection.
Medicinal chemistry optimization led to the identification of a highly
potent (0.8 nM) and selective inhibitor of HDAC8