Results 171 to 180 of about 3,273,294 (390)

Bayesian Meta‐Learning for Few‐Shot Reaction Outcome Prediction of Asymmetric Hydrogenation of Olefins

Angewandte Chemie, EarlyView.
A Bayesian meta‐learning framework is proposed for reaction outcome prediction in low‐data settings. It utilizes a literature‐mined dataset on asymmetric hydrogenation of olefins to build a pre‐trained model. This meta‐model is shown to return better predictions as compared to single‐tasks methods, such as random forest and graph neural networks, given
Sukriti Singh, José Miguel Hernández‐Lobato   +1 more
wiley   +2 more sources

Enantioselective Synthesis of the C(1)-C(6?) Subunit of Zaragozic Acid C

Journal of the Brazilian Chemical Society, 1998
Preparation of the C(1)-C(6?) subunit of Zaragozic acid C is described. The C(5?) methyl-bearing stereocenter is installed by rapid, regioselective opening of a phenylcyclopropyl carbinol with Pearlman?s catalyst (1 atm H2) in 2% triflic acid/methanol.
Carreira Erick M., Ledford Brian E.
doaj  

Applications of Nanozymes in Chiral-Molecule Recognition through Electrochemical and Ultraviolet–Visible Analysis

Molecules
Chiral molecules have similar physicochemical properties, which are different in terms of physiological activities and toxicities, rendering their differentiation and recognition highly significant. Nanozymes, which are nanomaterials with inherent enzyme-
Jing-Jing Dai, Guo-Ying Chen, Lei Xu, Huan Zhu, Feng-Qing Yang   +4 more
doaj   +1 more source

Enantioselective Synthesis of Cyclobutenes by Intermolecular [2+2] Cycloaddition with Non-C2 Symmetric Digold Catalysts

Journal of the American Chemical Society, 2017
The enantioselective intermolecular gold(I)-catalyzed [2+2] cycloaddition of terminal alkynes and alkenes has been achieved using non-C2-chiral Josiphos digold(I) complexes as catalysts, by the formation of the monocationic complex. This new approach has
Cristina García‐Morales, Beatrice Ranieri, Imma Escofet, Laura López-Suárez, C. Obradors, A. Konovalov, A. Echavarren   +6 more
semanticscholar   +1 more source

Enantioselective Total Synthesis of (−)-Dactylolide

Organic Letters, 2006
[reaction: see text] The enantioselective total synthesis of (-)-dactylolide is reported. The absolute stereochemistry of the tetrahydropyran was established by catalytic asymmetric Jacobsen hetero-Diels-Alder reaction. The remote C19 stereocenter was introduced by a sequence of chelation-controlled Grignard addition and Ireland-Claisen rearrangement.
Louis, Ignace, L. Hungerford, Natasha, J. Humphries, Edward, D. McLeod, Malcolm   +3 more
openaire   +4 more sources

Structural Basis of Sequential Enantioselective Epoxidation by a Flavin‐Dependent Monooxygenase in Lasalocid A Biosynthesis

Angewandte Chemie, EarlyView.
Lsd18 is a flavin‐dependent monooxygenase from Streptomyces lasalocidi that performs two enantioselective epoxidations during lasalocid A biosynthesis. X‐ray crystal structures of Lsd18 bound to a substrate and product analogue illuminate how this enzyme performs multiple epoxidations on the same substrate molecule and how it controls stereoselectivity.
Qian Wang, Yaming Deng, Dayan Viera, Xiaopeng Liu, Ning Liu, Yulu Hu, Xiangdong Hu, Hao Wei, Quan Zhou, Ting Lan, Wei He, Xi Chen, Chu‐Young Kim   +12 more
wiley   +2 more sources

Stereoselective total synthesis and enantioselective formal synthesis of the antineoplastic sesquiterpene quinone metachromin A

Journal of the Brazilian Chemical Society, 1999
The first total synthesis of the antineoplastic marine natural product metachromin-A (1) was accomplished through a convergent synthetic approach amenable to the preparation of analogues for biological studies.
Almeida Wanda P., Correia Carlos Roque D.   +1 more
doaj  

A carbohydrate approach for the formal total synthesis of (−)-aspergillide C

Beilstein Journal of Organic Chemistry, 2014
An enantioselective formal total synthesis of aspergillide C is accomplished using commercially available tri-O-acetyl-D-galactal employing a Ferrier-type C-glycosylation, utilizing a Trost hydrosilylation and protodesilylation as key reactions.
Pabbaraja Srihari, Namballa Hari Krishna, Ydhyam Sridhar, Ahmed Kamal   +3 more
doaj   +1 more source

Iridium‐Catalyzed Asymmetric Allenylic Substitution via Kinetic Resolution Enabled by New Monodentate Ligands

Angewandte Chemie, EarlyView.
The first kinetic resolution of allenylic alcohols by asymmetric allenylic substitution has been achieved, which was enabled by the design of a new chiral ligand that altered the energetic profiles of the previously established pathways. Both secondary and tertiary alcohols were suitable substrates.
Youshao Tu, Xiangfeng Lin, Jie Lin, Chaoshen Zhang, Jianwei Sun   +4 more
wiley   +2 more sources

Recent Developments in Enantioselective Phase Transfer Catalysis Using Chiral Ammonium Salts

CHIMIA, 2006
Due to the constant demand for non-racemic molecules in both industrial and academic laboratories, many efforts have been devoted in the last 25 years to the development of enantioselective phase transfer catalyzed (PTC) processes.
Jérôme Vachon, Jérôme Lacour
doaj   +1 more source