Organocatalytic Enantioselective Direct Vinylogous Michael Addition of α,β-Unsaturated γ‑Butyrolactam to β‑Acyl Acrylates and 1,2-Diacylethylenes

A highly efficient Michael addition of α,β-unsaturated γ-butyrolactam to various β-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 α-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 Diels–Alder reaction and a stepwise Michael addition, for the formation of corresponding products

G2/M-Phase-Inhibitory Mitochondrial-Depolarizing Re(I)/Ru(II)/Ir(III)-2,2′-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)-2,2′-bipyrimidine complexes [L′Re2], [L′RuRe], and [L′IrRe] 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 [L′IrRe] has displayed significant potency among all the three complexes with an IC50 value of 24.12 μM. The complex [L′IrRe] 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)­aryl 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)­arene, 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