نتایج جستجو برای: chiral auxiliaries

تعداد نتایج: 38094  

Journal: :Chemical communications 2010
Iria Louzao José Manuel Seco Emilio Quiñoá Ricardo Riguera

(13)C NMR, alone or in combination with (1)H NMR, allows the assignment of the absolute configuration of chiral alcohols, amines, carboxylic acids, thiols, cyanohydrins, sec,sec-diols and sec,sec-aminoalcohols, derivatized with appropriate chiral auxiliaries. This extends the assignment possibilities of NMR to fully deuterated and to nonproton containing compounds.

2013
Quynh Pham Bao Nguyen Taek Hyeon Kim

Asymmetric alkylation reactions using non-cross-linked polystyrene (NCPS)-supported 2-imidazolidinone chiral auxiliaries were successfully investigated with excellent diastereocontrol (>99% de). The recovery and the recycling of this soluble polymer-supported chiral auxiliary were achieved in order to produce highly optical pure carboxylic acids.

Journal: :Chemical communications 2014
Christina M McSweeney Vera M Foley Gerard P McGlacken

The asymmetric alkylation of ketones represents a fundamental transformation in organic chemistry. Chiral auxiliaries have been used almost exclusively for this transformation. Herein we describe a strategy for the generation of enantiomerically enriched α-alkylated ketones up to an er of 83 : 17, using a chiral ligand protocol.

2015
Mathias Pichler Johanna Novacek Raphaël Robiette Vanessa Poscher Markus Himmelsbach Uwe Monkowius Norbert Müller Mario Waser

The use of carbonyl-stabilised ammonium ylides to access chiral glycidic amides and the corresponding aziridines has so far been limited to racemic trans-selective protocols. We herein report the development of an asymmetric approach to access such compounds with high levels of stereoselectivity using easily accessible chiral auxiliary-based ammonium ylides. The use of phenylglycinol as the chi...

Journal: :Symmetry 2018
Mohammed Hasan Victor Borovkov

Helicenes are unique helical chromophores possessing advanced and well-controlled spectral and chemical properties owing to their diverse functionalization and defined structures. Specific modification of these molecules by introducing aromatic rings of differing nature and different functional groups results in special chiroptical properties, making them effective chiral auxiliaries and supram...

Journal: :Chemical communications 2008
Kévin M Joly Claire Wilson Alexander J Blake James H R Tucker Christopher J Moody

Planar chirality associated with the ferrocene in ferrocenyl oximes and hydrazones bearing chiral auxiliaries effectively competes with or overrides the normally excellent stereocontrol afforded by the auxiliary in determining the diastereoselectivity of addition to the C=N bond.

Journal: :Journal of Synthetic Organic Chemistry, Japan 1998

Journal: :Angewandte Chemie 2015
Jan Prinz Oliver Gröning Harald Brune Roland Widmer

Intrinsically chiral surfaces of intermetallic compounds are shown to be novel materials for enantioselective processes. Their advantage is the significantly higher thermal and chemical stability, and therefore their extended application range for catalyzed chiral reactions compared to surfaces templated with chiral molecular modifiers or auxiliaries. On the Pd1 -terminated PdGa(111) surface, r...

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