6 research outputs found
Organocatalytic Enantioselective Direct Vinylogous Michael Addition of Ī±,Ī²-Unsaturated Ī³āButyrolactam to Ī²āAcyl Acrylates and 1,2-Diacylethylenes
A highly
efficient Michael addition of Ī±,Ī²-unsaturated Ī³-butyrolactam
to various Ī²-acyl acrylates and ene-diones to provide synthetically
useful compounds was developed. The products were obtained with high
diastereo- and enantioselectivities (up to >25:1 dr and 99% ee)
containing adjacent tertiary stereocenters
Chemoselective Intramolecular Wittig Reactions for the Synthesis of Oxazoles and Benzofurans
A chemoselective approach was developed
for the synthesis of highly
functionalized oxazoles and benzofurans using an intramolecular Wittig
reaction as the key step. By choosing proper trapping reagent or method
of addition of reagents, chemoselectivity can be controlled toward
either oxazole or benzofuran derivatives
Chemoselective Intramolecular Wittig Reactions for the Synthesis of Oxazoles and Benzofurans
A chemoselective approach was developed
for the synthesis of highly
functionalized oxazoles and benzofurans using an intramolecular Wittig
reaction as the key step. By choosing proper trapping reagent or method
of addition of reagents, chemoselectivity can be controlled toward
either oxazole or benzofuran derivatives
Expanding the Scope of Primary Amine Catalysis: Stereoselective Synthesis of Indanedione-Fused 2,6-Disubstituted <i>trans-</i>Spirocyclohexanones
A cinchona-alkaloid-derived chiral
primary-amine-catalyzed enantioselective
method for the synthesis of the thermodynamically less stable indanedione-fused
2,6-<i>trans</i>-disubstituted spirocyclohexanones is demonstrated.
Both the enantiomeric forms of the <i>trans</i> isomer are
obtained in excellent yields and enantioselectivities. Furthermore,
one of the enantiopure <i>trans</i>-spiranes bearing an
additional Ī±-substitution on the cyclohexanone ring was then
epimerized into its thermodynamically stable <i>cis</i> counterpart,
with little loss of enantioselectivity to demonstrate the feasibility
of such a transformation. Mechanistic investigations revealed two
competing pathways, a concerted DielsāAlder reaction and a
stepwise Michael addition, for the formation of corresponding products
G2/M-Phase-Inhibitory Mitochondrial-Depolarizing Re(I)/Ru(II)/Ir(III)-2,2ā²-Bipyrimidine-Based Heterobimetallic Luminescent Complexes: An Assessment of In Vitro Antiproliferative Activity and Bioimaging for Targeted Therapy toward Human TNBC Cells
Triple-negative breast cancer (TNBC) is an extremely
vicious subtype
of human breast cancer having the worst prognosis along with strong
invasive and metastatic competency. Hence, it can easily invade into
blood vessels, and presently, no targeted therapeutic approach is
available to annihilate this type of cancer. Metal complexes have
successfully stepped into the anticancer research and are now being
applauded due to their anticancer potency after the discovery of cisplatin.
Many of these metal complexes are also well recognized for their activity
toward breast cancer. As the TNBC is a very dangerous subtype and
has long been a challenging ailment to treat, we have intended to
develop a few brand new mixed metallic Ru(II)/Ir(III)/Re(I)-2,2ā²-bipyrimidine
complexes [Lā²Re2], [Lā²RuRe], and [Lā²IrRe] to abate the unbridled proliferation
of TNBC cells. The potency of the complexes against TNBC cells has
been justified using MDA-MB-468 TNBC cell lines where complex [Lā²IrRe] has displayed significant potency among all
the three complexes with an IC50 value of 24.12 Ī¼M.
The complex [Lā²IrRe] has been competent to cause
apoptosis of TNBC cells through inhibition of the G2/M phase in the
cell cycle in association with a profuse amount of ROS generation
and mitochondrial depolarization
Stereoselective Synthesis of <i>o</i>-Bromo (or Iodo)aryl P-Chirogenic Phosphines Based on Aryne Chemistry
The efficient synthesis of chiral or achiral tertiary
phosphines
bearing an <i>o</i>-bromo (or iodo)Āaryl substituent is described.
The key step of this synthesis is based on the reaction of a secondary
phosphine borane with the 1,2-dibromo (or diiodo)Āarene, owing to the
formation in situ of an aryne species in the presence of <i>n</i>-butyllithium. When P-chirogenic secondary phosphine boranes were
used, the corresponding <i>o</i>-halogeno-arylphosphine
boranes were obtained without racemization in moderate to good yields
and with ee up to 99%. The stereochemistry of the reaction, with complete
retention of the configuration at the P atom, has been established
by X-ray structures of P-chirogenic <i>o</i>-halogenophenyl
phosphine borane complexes. The decomplexation of the borane was easily
achieved without racemization using DABCO to obtain the free <i>o</i>-halogeno-arylphosphines in high yields