نتایج جستجو برای: asymmetric transformation

تعداد نتایج: 285010  

2007
Lotte Holmegaard Simon S. Viftrup Vinod Kumarappan Christer Z. Bisgaard Henrik Stapelfeldt Edward Hamilton Tamar Seideman

We combine newly developed experimental and theoretical methods to explore and control the rotations of asymmetric top molecules. In the low-temperature limit, the revival spectra of laser-driven rotational wave packets exhibit a fascinating quantum-mechanical structure, which is qualitatively different for asymmetric tops compared to symmetric or linear tops. With increasing fluence, the struc...

Journal: :Organic letters 2015
David Sandoval Andrey V Samoshin Javier Read de Alaniz

The first example of a general asymmetric nitrosocarbonyl hetero-ene reaction is described. The procedure uses a copper-catalyzed aerobic oxidation of a commercially available chiral nitrosocarbonyl precursor (EleNOr) and is operationally simple. The transformation is both high yielding and highly diastereoselective for a range of silyl enol ether derivatives. A variety of synthetically useful ...

Journal: :Chemical Society Reviews 2021

Atroposelective transformations of (hetero)biaryls are classified into desymmetrization, kinetic resolution, dynamic and asymmetric transformation depending on the nature behavior starting material.

Journal: :Environmental science & technology 2004
Ye Zhuang Jeffrey S Thompson Christopher J Zygarlicke John H Pavlish

A bench-scale entrained-flow reactor was used to extract flue gas produced by burning a subbituminous Belle Ayr coal in a 580-MJ/h combustion system. The reactor was operated at 400 degrees, 275 degrees, and 150 degrees C with a flow rate corresponding to residence times of 0-7 s. Transformations of elemental mercury (Hg0) and total gas mercury (Hg(gas)) in the reactor were evaluated as functio...

Journal: :Molecules 2012
Seung-Mann Paek

Fully substituted olefin generation via metathesis is presented. Catalyst development, optimization of reaction conditions and substrate screening are included. In addition, asymmetric alkene metathesis, the cross metathesis reaction for this transformation and its application in natural products will be discussed.

Journal: :Chemical communications 2012
Zulfa Yoosuf-Aly Juan A Faraldos David J Miller Rudolf K Allemann

The enzyme-guided asymmetric synthesis of (+)-verbenone from geranyl diphosphate in a simple two-step, one pot transformation highlights the potential of chemoenzymatic procedures for the generation of high-value terpenoids.

Journal: :Journal of the American Chemical Society 2009
Zhi-Yong Han Han Xiao Xiao-Hua Chen Liu-Zhu Gong

Consecutive hydroamination/asymmetric transfer hydrogenation under relay catalysis of an achiral gold complex/chiral Brønsted acid binary system has been described for the direct transformation of 2-(2-propynyl)aniline derivatives into tetrahydroquinolines with high enantiomeric purity.

2014
Yan Zhang Pornrapee Vongvilai Morakot Sakulsombat Andreas Fischer Olof Ramström

Dynamic systems based on consecutive thia-Michael and Henry reactions were generated and transformed using lipase-catalyzed asymmetric transformation. Substituted thiolane structures with three contiguous stereocenters were resolved in the process in high yields and high enantiomeric excesses.

2014
Ye Zhu Stephen L. Buchwald

A palladium-catalyzed asymmetric arylation of 9-aminofluorene-derived imines using a chiral dialkylbiaryl phosphine as the supporting ligand has been developed. This transformation allows for enantioselective access to a diverse range of α-branched benzylamines.

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