A5055225447- Asymmetric Synthesis and Catalysis
- Asymmetric Hydrogenation and Catalysis
- Synthetic Organic Chemistry Methods
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Catalytic C–H Functionalization Methods
- Crystallography and molecular interactions
- Oxidative Organic Chemistry Reactions
- Marine Sponges and Natural Products
- Chemical Reactions and Isotopes
- Axial and Atropisomeric Chirality Synthesis
- T-cell and B-cell Immunology
- Chemical Synthesis and Reactions
- Synthesis and Catalytic Reactions
- Biochemical and Molecular Research
- HIV/AIDS drug development and treatment
- Antibiotic Resistance in Bacteria
- Berberine and alkaloids research
- Hematopoietic Stem Cell Transplantation
- Enzyme Structure and Function
- Chemical Synthesis and Analysis
- Evolution and Genetic Dynamics
- Porphyrin Metabolism and Disorders
The University of Texas Southwestern Medical Center
2021-2023
Indian Institute of Science Bangalore
2012-2022
Center for Systems Biology
2021
Bangalore University
2014-2017
An organocatalytic enantioselective formal C(sp(2))-H alkylation is reported. This alkylative desymmetrization of prochiral 2,2-disubstituted cyclopentene-1,3-dione catalyzed by a bifunctional tertiary aminourea derivative, utilizes air-stable and inexpensive nitroalkanes as the alkylating agents, delivers synthetically versatile five-membered carbocycles containing an all-carbon quaternary stereogenic center remote from reaction site in excellent enantioselectivity.
An efficient, robust and highly enantioselective catalytic desymmetrization of 2,2-disubstituted cyclopentene-1,3-diones is developed <italic>via</italic> direct vinylogous nucleophilic addition deconjugated butenolides.
Abstract The antibiotic trimethoprim (TMP) is used to treat a variety of Escherichia coli infections, but its efficacy limited by the rapid emergence TMP-resistant bacteria. Previous laboratory evolution experiments have identified resistance-conferring mutations in gene encoding TMP target, bacterial dihydrofolate reductase (DHFR), particular mutation L28R. Here, we show that 4’-desmethyltrimethoprim (4’-DTMP) inhibits both DHFR and L28R variant, selects against bacteria carry experiments....
A direct vinylogous Michael reaction of γ-substituted deconjugated butenolides with nitroolefins has been developed the help a newly identified quinine-derived bifunctional catalyst, allowing synthesis densely functionalized products contiguous quaternary and tertiary stereocenters in excellent yield perfect diastereoselectivity (>20:1 dr) high enantioselectivity (up to 99:1 er).
Competition under control: A practical and efficient direct asymmetric vinylogous Michael reaction of deconjugated butenolides has been developed (see scheme). The products this reaction, highly functionalized chiral succinimides, are obtained in excellent yield with high diastereoselectivity (up to d.r.=18:1) outstanding enantioselectivity e.r.=99.5:0.5).
An enantioselective formal C(sp2 )-H vinylation of prochiral 2,2-disubstituted cyclopentene-1,3-dione is presented. This vinylative desymmetrization realized by using a two-step procedure that consists catalytic vinylogous Michael addition deconjugated butenolides to and base-mediated decarboxylation. The overall process utilizes as the source highly substituted vinyl unit. Five-membered carbocycles containing remote all-carbon quaternary stereogenic center are obtained in good yields with...
Experimental 13C kinetic isotope effects (KIEs) and density functional theory (DFT) calculations are used to evaluate the mechanism origin of enantioselectivity in formal C(sp2)–H alkylative desymmetrization cyclopentene-1,3-diones using nitroalkanes as alkylating agent. An unusual combination an inverse (∼0.980) a normal (∼1.033) KIE is observed on bond-forming carbon atoms cyclopentene-1,3-dione nitroalkane, respectively. These data provide strong support for involving reversible...
A formal <italic>umpolung</italic> strategy is presented for the enantioselective installation of an alkenyl group with a terminal double bond at tertiary center. This one-pot two-step sequence relies on unique features nitro group, which after inverting polarity alkenylating agent toward desired formation, itself serves as leaving group.
We report a copper-catalyzed, regioselective, and stereospecific alkylation of unbiased internal allylic carbonates with functionalized alkyl aryl Grignard reagents. The reactions exhibit high stereospecificity regioselectivity for either S
A DRB1*1503 allele not associated with DRB5 locus has been detected in an African family during routine HLA typing for bone marrow transplantation. PCR/SSOP analysis showed the DR2-associated alleles all members but appeared to be absent patient and his brother. The samples were then analyzed presence of DRB6 pseudogenes we found that unusual haplotype was DRB6*0101 allele. This finding strengthen hypothesis a recombination hot spot between DRB1 genes.
ABSTRACT: Experimental 13C kinetic isotope effects (KIEs) and DFT calculations are used to evaluate the mecha-nism origin of enantioselectivity in C(sp2)‒H alkylative desymmetrization cyclopentene-1,3-diones using nitroalkanes as alkylating agent. An unusual combination an inverse (~0.980) a normal (~1.030) KIE is observed on bond-forming carbon atoms cyclopentene-1,3-dione nitroalkane, respectively. These data provide strong support for mechanism involving reversible carbon-carbon...
Abstract Review: [27 refs.
Abstract The alkylative desymmetrization of prochiral 2,2‐disubstituted cyclopentene‐1,3‐diones with nitroalkanes using a quinine‐derived chiral catalyst is described.
Abstract A practical and efficient direct asymmetric vinylogous Michael reaction of deconjugated butenolides is developed.
Abstract We report a copper‐catalyzed, regioselective, and stereospecific alkylation of unbiased internal allylic carbonates with functionalized alkyl aryl Grignard reagents. The reactions exhibit high stereospecificity regioselectivity for either S N 2 or 2′ products under two sets copper‐catalyzed conditions, which enables the preparation broad range E ‐alkene selectivity. Density functional theory calculations reveal origins based on different behaviors homo‐ heterocuprates.