Track topics on Twitter Track topics that are important to you
A diastereoselective (up to >99%) route to all carbon quaternary stereocenters at the C-3 position of cyclic lactams has been developed via Johnson-Claisen rearrangement of γ-hydroxy-α,β-unsaturated lactams. It has been observed that olefin geometry plays an important role in the development of the absolute stereochemistry of the product. Dependence of product configuration on the olefin geometry is explained by postulating probable transition states. The success of this method has been shown for multigram-scale synthesis of these substituted lactams from commercially available cheap starting materials. The synthetic usefulness of this method is also demonstrated by carrying out the total synthesis of (-)-physostigmine.
This article was published in the following journal.
Name: Organic letters
We report an asymmetric synthesis of chiral boryl-functionalized γ-lactams containing all-carbon quaternary stereocenters via a Co-catalyzed enantioselective hydroboration/cyclization of amide-tether...
The development of the first enantioselective transition metal-catalyzed allylic alkylation providing access to acyclic products bearing vicinal all-carbon quaternary centers is disclosed. The iridium...
A new and modular electrophilic trifluoromethylthiolation/semipinacol rearrangement of allylic silyl ethers has been developed under mild conditions. This approach allows the formation of a number of ...
Cyclopropenylcarbinyl cyanates, generated in situ by dehydration of the corresponding carbamates, undergo an efficient and stereoselective [3,3]-sigmatropic rearrangement leading to the corresponding ...
Cyclic ketones bearing alpha-quaternary stereocenters undergo efficient kinetic resolution using cyclohexanone monooxygenase (CHMO) from Acinetobacter calcoaceticus. Lactones possessing tetrasubstitut...
The purpose of this study is to evaluate the safety and tolerability of two carbon monoxide doses when administered as an inhaled gas for 1 hour in patients receiving kidney transplants.
We aim to test our method for measuring chemosensitivity (the ventilatory response to a change in carbon dioxide), which uses sinusoidal carbon dioxide stimuli. Hypotheses: - Ca...
The purpose of this study is to determine whether a relationship exists between EtCO2 and carboxyhemoglobin levels in carbon monoxide exposure. Our hypothesis is that a liner relationship ...
Carbon-12 and carbon-13 are naturally-abundant isotopes in exhaled breath carbon dioxide. The ratio of carbon-13 to carbon-12 in exhaled breath is known as the breath delta value. This stu...
Carbon dioxide insufflation during colonoscopy significantly reduces discomfort (pain, bloating and flatulence) after the procedure. So far, it has not been studied in inflammatory bowel d...
Unsaturated derivatives of the ESTRANES with methyl groups at carbon-13, with no carbon at carbon-10, and with no more than one carbon at carbon-17. They must contain one or more double bonds.
Enzymes that catalyze the joining of two molecules by the formation of a carbon-carbon bond. These are the carboxylating enzymes and are mostly biotinyl-proteins. EC 6.4.
Enzymes that catalyze the cleavage of a carbon-carbon bond by means other than hydrolysis or oxidation. This subclass contains the DECARBOXYLASES, the ALDEHYDE-LYASES, and the OXO-ACID-LYASES. EC 4.1.
Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.
Enzymes that catalyze the shifting of a carbon-carbon double bond from one position to another within the same molecule. EC 5.3.3.
Alliances Astrazeneca Bioethics Boehringer Clinical Research Organization Collaborations GSK Johnson & Johnson Lilly Merck Mergers and Acquisitions Nexium Novartis Pfizer Roche Sanofi ...