scholarly journals Spiro-fused carbohydrate oxazoline ligands: Synthesis and application as enantio-discrimination agents in asymmetric allylic alkylation

2016 ◽  
Vol 12 ◽  
pp. 166-171 ◽  
Author(s):  
Jochen Kraft ◽  
Martin Golkowski ◽  
Thomas Ziegler
Keyword(s):  
Asymmetric Catalysis ◽  
Enantiomeric Excess ◽  
Asymmetric Induction ◽  
Allylic Alkylation ◽  
Dimethyl Malonate ◽  
Thiocyanic Acid ◽  
Convenient Synthesis ◽  
Palladium Catalyzed ◽  
Acidic Conditions ◽  
Oxazoline Ligands

In the present work, we describe a convenient synthesis of spiro-fused D-fructo- and D-psico-configurated oxazoline ligands and their application in asymmetric catalysis. The ligands were synthesized from readily available 3,4,5-tri-O-benzyl-1,2-O-isopropylidene-β-D-fructopyranose and 3,4,5-tri-O-benzyl-1,2-O-isopropylidene-β-D-psicopyranose, respectively. The latter compounds were partially deprotected under acidic conditions followed by condensation with thiocyanic acid to give an anomeric mixture of the corresponding 1,3-oxazolidine-2-thiones. The anomeric 1,3-oxazolidine-2-thiones were separated after successive benzylation, fully characterized and subjected to palladium catalyzed Suzuki–Miyaura coupling with 2-pyridineboronic acid N-phenyldiethanolamine ester to give the corresponding 2-pyridyl spiro-oxazoline (PyOx) ligands. The spiro-oxazoline ligands showed high asymmetric induction (up to 93% ee) when applied as chiral ligands in palladium-catalyzed allylic alkylation of 1,3-diphenylallyl acetate with dimethyl malonate. The D-fructo-PyOx ligand provided mainly the (R)-enantiomer while the D-psico-configurated ligand gave the (S)-enantiomer with a lower enantiomeric excess.

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.

Palladium-catalyzed asymmetric allylic alkylation using dimethyl malonate and its derivatives as nucleophile

1991 ◽  
Vol 2 (7) ◽  
pp. 663-666 ◽  
Author(s):  
Motowo Yamaguchi ◽  
Toshihide Shima ◽  
Takamichi Yamagishi ◽  
Mitsuhiko Hida
Keyword(s):  
Allylic Alkylation ◽  
Dimethyl Malonate ◽  
Asymmetric Allylic Alkylation ◽  
Palladium Catalyzed

Chiral Phosphaalkene−Oxazoline Ligands for the Palladium-Catalyzed Asymmetric Allylic Alkylation

2010 ◽  
Vol 12 (20) ◽  
pp. 4667-4669 ◽  
Author(s):  
Julien Dugal-Tessier ◽  
Gregory R. Dake ◽  
Derek P. Gates
Keyword(s):  
Allylic Alkylation ◽  
Asymmetric Allylic Alkylation ◽  
Palladium Catalyzed ◽  
Oxazoline Ligands

scholarly journals Spiro Indane-Based Phosphine-Oxazolines as Highly Efficient P,N Ligands for Enantioselective Pd-Catalyzed Allylic Alkylation of Indoles and Allylic Etherification

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1575 ◽  
Author(s):  
Zhongxuan Qiu ◽  
Rui Sun ◽  
Kun Yang ◽  
Dawei Teng
Keyword(s):  
Aliphatic Alcohols ◽  
Allylic Alkylation ◽  
Indole Derivatives ◽  
Broad Scope ◽  
Palladium Catalyzed ◽  
Allylic Etherification ◽  
High Yields ◽  
Stereogenic Center ◽  
Optimized Conditions ◽  
Oxazoline Ligands

A series of indane-based phosphine-oxazoline ligands with a spirocarbon stereogenic center were examined for palladium-catalyzed asymmetric allylic alkylation of indoles. Under optimized conditions, high yields (up to 98%) and enantioselectivities (up to 98% ee) were obtained with a broad scope of indole derivatives. The ligand was determined to be the most efficient P,N-ligand for this reaction. Moreover, the ligand was also efficient for Pd-catalyzed asymmetric allylic etherification with hard aliphatic alcohols as nucleophiles.

Synthesis of highly rigid phosphine–oxazoline ligands for palladium-catalyzed asymmetric allylic alkylation

2018 ◽  
Vol 16 (41) ◽  
pp. 7717-7724 ◽  
Author(s):  
Zhongxuan Qiu ◽  
Rui Sun ◽  
Dawei Teng
Keyword(s):  
Catalytic Performance ◽  
Allylic Alkylation ◽  
Asymmetric Allylic Alkylation ◽  
Palladium Catalyzed ◽  
Alkylation Reactions ◽  
Stereogenic Center ◽  
Oxazoline Ligands ◽  
Excellent Catalytic Performance

Rigid phosphine–oxazoline ligands with a spirocarbon stereogenic center were developed, which exhibited excellent catalytic performance for Pd-catalyzed allylic alkylation reactions.

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