نتایج جستجو برای: desymmetrization

تعداد نتایج: 310  

Journal: :Chemical communications 2015
Yuxiao Liu Yongming Deng Peter Y Zavalij Renhua Liu Michael P Doyle

A highly stereoselective desymmetrization reaction of δ,δ-diaryl-α-diazo-β-ketoesters catalyzed by chiral dirhodium carboxylates forms aromatic cycloaddition products in up to 97% ee.

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2010
Hongming Li Xiaofeng Liu Fanghui Wu Liang Tang Li Deng

Complementary to enantioselective transformations of planar functionalities, catalytic desymmetrization of meso compounds is another fundamentally important strategy for asymmetric synthesis. However, experimentally established stereochemical models on how a chiral catalyst discriminates between two enantiotopic functional groups in the desymmetrization of a meso substrate are particularly lack...

Journal: :Chemical communications 2013
Zachary X Giustra Kian L Tan

Glycerol is an ideal building block for the synthesis of complex molecules, because it is inexpensive and highly functionalized. We report the desymmetrization of glycerol through silyl transfer, using a chiral organic catalyst in high yield and enantioselectivity.

Journal: :Journal of the American Chemical Society 2006
Steven T Staben Xin Linghu F Dean Toste

A cinchona-alkaloid catalyzed asymmetric Kornblum DeLaMare rearrangement has been developed. Thus, enantioenriched 4-hydroxyenones are prepared from dienes by a two-step sequence involving photochemical dioxygenation and chiral base-catalyzed desymmetrization of the resulting endoperoxides.

Journal: :Chemical communications 2011
Yan Zhang Choon Wee Kee Richmond Lee Xiao Fu Julian Ying-Teck Soh Esther Mun Foong Loh Kuo-Wei Huang Choon-Hong Tan

An amino-indanol derived chiral guanidine was developed as an efficient Brønsted base catalyst for the desymmetrization of meso-aziridines with both thiols and carbamodithioic acids as nucleophiles, which provided 1,2-difunctionalized ring-opened products in high yields and enantioselectivities.

2012
Hartmut Schedel Keizo Kan Yoshihiro Ueda Kenji Mishiro Keisuke Yoshida Takumi Furuta Takeo Kawabata

In this work we developed C(2)-symmetric chiral nucleophilic catalysts which possess a pyrrolidinopyridine framework as a catalytic site. Some of these organocatalysts effectively promoted asymmetric desymmetrization of meso-diols via enantioselective acylation.

Journal: :Organic & biomolecular chemistry 2012
David J Aitken Angela M Bernard Francesca Capitta Angelo Frongia Régis Guillot Jean Ollivier Pier Paolo Piras Francesco Secci Marco Spiga

N-Phenylsulfonyl (S)-proline catalyzes the direct aldol reaction of 3-substituted cyclobutanones and aryl aldehydes in good yield and with excellent diastereoselectivity and enantioselectivity. This desymmetrization process provides highly functionalized cyclobutanones with control over three contiguous stereogenic centers.

2014
Jacob S. Kanady Po-Heng Lin Kurtis M. Carsch Robert J. Nielsen Michael K. Takase William A. Goddard Theodor Agapie

Synthetic model compounds have been targeted to benchmark and better understand the electronic structure, geometry, spectroscopy, and reactivity of the oxygen-evolving complex (OEC) of photosystem II, a low-symmetry Mn4CaOn cluster. Herein, low-symmetry Mn(IV)3GdO4 and Mn(IV)3CaO4 cubanes are synthesized in a rational, stepwise fashion through desymmetrization by ligand substitution, causing si...

Journal: :Organic Chemistry: Current Research 2014

Journal: :Organic & biomolecular chemistry 2010
Simon J Byrne Anthony J Fletcher Paul Hebeisen Michael C Willis

A desymmetrization protocol has been used to develop a palladium catalyzed enantioselective carbonylation process. Achiral cyclic bis-alkenyltriflates are converted to their corresponding monoester derivatives with selectivities of up to 96% ee.

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