scholarly journals Asymmetric Addition Reaction of Phenyllithium to 1,2-Ethylenediimine with tbe Aid of A Chiral Ligand.

1997 ◽  
Vol 45 (10) ◽  
pp. 1705-1707 ◽  
Author(s):  
Daisuke TANIYAMA ◽  
Motomu KANAI ◽  
Akira IIDA ◽  
Kiyoshi TOMIOKA
Keyword(s):  
Addition Reaction ◽  
Chiral Ligand ◽  
Asymmetric Addition

A new pyrrolidine-derived atropisomeric amino alcohol as a highly efficient chiral ligand for the asymmetric addition of diethylzinc to aldehydes

2014 ◽  
Vol 55 (50) ◽  
pp. 6891-6894 ◽  
Author(s):  
Ferenc Faigl ◽  
Zsuzsa Erdélyi ◽  
Szilvia Deák ◽  
Miklós Nyerges ◽  
Béla Mátravölgyi
Keyword(s):  
Amino Alcohol ◽  
Chiral Ligand ◽  
Asymmetric Addition ◽  
Highly Efficient

Structural requirements of a chiral ligand for the catalytic asymmetric addition of thiophenol to α,β-unsaturated esters

1998 ◽  
Vol 39 (15) ◽  
pp. 2141-2144 ◽  
Author(s):  
Kiyoshi Tomioka ◽  
Manabu Okuda ◽  
Katsumi Nishimura ◽  
Shino Manabe ◽  
Motomu Kanai ◽  
...  
Keyword(s):  
Chiral Ligand ◽  
Structural Requirements ◽  
Asymmetric Addition ◽  
Unsaturated Esters ◽  
Catalytic Asymmetric

ChemInform Abstract: A New Pyrrolidine-Derived Atropisomeric Amino Alcohol as a Highly Efficient Chiral Ligand for the Asymmetric Addition of Diethylzinc to Aldehydes.

ChemInform ◽  
2015 ◽  
Vol 46 (18) ◽  
pp. no-no
Author(s):  
Ferenc Faigl ◽  
Zsuzsa Erdelyi ◽  
Szilvia Deak ◽  
Miklos Nyerges ◽  
Bela Matravoelgyi
Keyword(s):  
Amino Alcohol ◽  
Chiral Ligand ◽  
Asymmetric Addition ◽  
Highly Efficient

scholarly journals (±)-trans-1,2-Cyclohexanediamine-Based Bis(NHC) Ligand for Cu-Catalyzed Asymmetric Conjugate Addition Reaction

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 780 ◽  
Author(s):  
Azusa Ishibashi ◽  
Shun Kamihigashi ◽  
Yuuki Iwai ◽  
Satoshi Sakaguchi
Keyword(s):  
Catalytic System ◽  
Amino Alcohol ◽  
Addition Reaction ◽  
Conjugate Addition ◽  
Addition Reactions ◽  
Chiral Ligand ◽  
Facial Selectivity ◽  
Ligand Precursors ◽  
Optically Pure

Bis(NHC) ligand precursors, L1, based on trans-1,2-diaminocyclohexane were designed and synthesized. To introduce chirality at the hydroxyamide side arm on the NHC of L1, a chiral β-amino alcohol, such as enantiopure leucinol, was used. Cu-catalyzed asymmetric conjugate addition reactions of cyclic and acyclic enones with Et2Zn were selected to evaluate the performance of L1 as a chiral ligand. For the reaction of cyclic enone, a combination of [bis(trimethylsilyl)acetylene]-(hexafluoroacetylacetonato)copper(I) (Cu(hfacac)(btmsa)) with a (±)-trans-1,2-cyclohexanediamine-based bis(NHC) ligand precursor, (rac; S,S)-L1, which was prepared from (S)-leucinol, was the most effective. Thus, treating 2-cyclohexen-1-one (3) with Et2Zn in the presence of catalytic amounts of Cu(hfacac)(btmsa) and (rac; S,S)-L1 afforded (R)-3-ethylcyclohexanone ((R)-4) with 97% ee. Similarly, use of (rac; R,R)-L1, which was prepared from (R)-leucinol, produced (S)-4 with 97% ee. Conversely, for the asymmetric 1,4-addition reaction of the acyclic enone, optically pure (−)-trans-1,2-cyclohexanediamine-based bis(NHC) ligand precursor, (R,R; S,S)-L1, worked efficiently. For example, 3-nonen-2-one (5) was reacted with Et2Zn using the CuOAc/(R,R; S,S)-L1 catalytic system to afford (R)-4-ethylnonan-2-one ((R)-6) with 90% ee. Furthermore, initially changing the counterion of the Cu precatalyst between an OAc and a ClO4 ligand on the metal reversed the facial selectivity of the approach of the substrates. Thus, the conjugate addition reaction of 5 with Et2Zn using the Cu(ClO4)2/(R,R; S,S)-L1 catalytic system, afforded (S)-6 with 75% ee.

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