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.

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-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.

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