scholarly journals Novel 3,4-Diarylpyrrolidine-Based Chiral Ligands for the Asymmetric Reaction of Arylmagnesium Bromides with Aldehydes

1987 ◽  
Vol 16 (1) ◽  
pp. 65-68 ◽  
Author(s):  
Kiyoshi Tomioka ◽  
Makoto Nakajima ◽  
Kenji Koga
Keyword(s):  
Chiral Ligands ◽  
Asymmetric Reaction

scholarly journals Synthesis and Evaluation of C2-Symmetric SPIROL-Based bis-Oxazoline Ligands

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1667
Author(s):  
Siyuan Sun ◽  
Nicolas A. Diaz ◽  
Pavel Nagorny
Keyword(s):  
Chiral Ligands ◽  
Asymmetric Reaction ◽  
Insertion Product ◽  
Oxazoline Ligands ◽  
Excellent Selectivity

This communication describes the synthesis of new bis-oxazoline chiral ligands (SPIROX) derived from the C2-symmetric spirocyclic scaffold (SPIROL). The readily available (R,R,R)-SPIROL (2) previously developed by our group was subjected to a three-step sequence that provided key diacid intermediate (R,R,R)-7 in 75% yield. This intermediate was subsequently coupled with (R)- and (S)-phenylglycinols to provide diastereomeric products, the cyclization of which led to two diastereomeric SPIROX ligands (R,R,R,R,R)-3a and (R,R,R,S,S)-3b in 85% and 79% yield, respectively. The complexation of (R,R,R,R,R)-3a and (R,R,R,S,S)-3b with CuCl and Cu(OTf)2 resulted in active catalysts that promoted the asymmetric reaction of α-diazopropionate and phenol. The resultant O–H insertion product was formed in 88% yield, and with excellent selectivity (97% ee) when ligand (R,R,R,R,R)-3a was used.

Synthesis of Axially Chiral 2,2’-Bisphosphobiarenes via a Nickel-Catalyzed Asymmetric Ullmann Coupling: General Access to Privileged Chiral Ligands without Optical Resolution

2020 ◽  
Author(s):  
Ziqing Zuo ◽  
Raphael Kim ◽  
Donald Watson
Keyword(s):  
Optical Resolution ◽  
Chiral Ligands ◽  
Chiral Auxiliaries ◽  
Axially Chiral ◽  
Ullmann Coupling

<div><p>We report an asymmetric Ullmann-type homocoupling of <i>ortho-</i>(iodo)arylphosphine oxides and <i>ortho</i>-(iodo)arylphosphonates that results in highly enantioenriched axially chiral bisphosphine oxides and bisphosphonates in good yields and excellent enantioselectivities. These products are readily converted to enantioenriched biaryl bisphosphines without need for chiral auxiliaries or optical resolution. This process provides a straightforward and practical route for the development of previously uninvestigated atroposelective biaryl bisphosphine ligands.</p></div>

Asymmetric Reaction is Rational Behavior

2014 ◽  
Author(s):  
Philip A. Horvath ◽  
Amit K. Sinha
Keyword(s):  
Rational Behavior ◽  
Asymmetric Reaction

Novel Chiral Ligands for Palladium-catalyzed Asymmetric Allylic Alkylation/ Asymmetric Tsuji-Trost Reaction: A Review

2019 ◽  
Vol 23 (11) ◽  
pp. 1168-1213 ◽  
Author(s):  
Samar Noreen ◽  
Ameer Fawad Zahoor ◽  
Sajjad Ahmad ◽  
Irum Shahzadi ◽  
Ali Irfan ◽  
...  
Keyword(s):  
Asymmetric Catalysis ◽  
Enantioselective Synthesis ◽  
Chiral Ligands ◽  
Allylic Alkylation ◽  
Research Groups ◽  
Asymmetric Allylic Alkylation ◽  
Catalytic Potential ◽  
Long Time ◽  
Palladium Catalyzed ◽  
Alkylation Reactions

Background: Asymmetric catalysis holds a prestigious role in organic syntheses since a long time and chiral inductors such as ligands have been used to achieve the utmost desired results at this pitch. The asymmetric version of Tsuji-Trost allylation has played a crucial role in enantioselective synthesis. Various chiral ligands have been known for Pdcatalyzed Asymmetric Allylic Alkylation (AAA) reactions and exhibited excellent catalytic potential. The use of chiral ligands as asymmetric inductors has widened the scope of Tsuji-Trost allylic alkylation reactions. Conclusion: Therefore, in this review article, a variety of chiral inductors or ligands have been focused for palladium catalyzed asymmetric allylic alkylation (Tsuji-Trost allylation) and in this regard, recently reported literature (2013-2017) has been described. The use of ligands causes the induction of enantiodiscrimination to the allylated products, therefore, the syntheses of various kinds of ligands have been targeted by many research groups to employ in Pd-catalyzed AAA reactions.

cis-Dioxomolybdenum(VI) Complexes Containing Chiral Ligands: Synthesis and Catalytic Application in Olefin Epoxidation

2011 ◽  
Vol 1 (2) ◽  
pp. 131-139 ◽  
Author(s):  
Jose A. Brito ◽  
Nathalie Saffon ◽  
Montserrat Gomez ◽  
Beatriz Royo
Keyword(s):  
Chiral Ligands ◽  
Olefin Epoxidation ◽  
Catalytic Application

ChemInform Abstract: Synthesis of New Chiral Ligands Based on Thiophene Derivatives for Use in Catalytic Asymmetric Oxidation of Sulfides.

ChemInform ◽  
2011 ◽  
Vol 42 (31) ◽  
pp. no-no
Author(s):  
Yong-Chul Jeong ◽  
Dae-Jun Ahn ◽  
Woo-Sun Lee ◽  
Seung-Han Lee ◽  
Kwang-Hyun Ahn
Keyword(s):  
Chiral Ligands ◽  
Asymmetric Oxidation ◽  
Oxidation Of Sulfides ◽  
Thiophene Derivatives ◽  
Catalytic Asymmetric
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