252873-91-9Relevant academic research and scientific papers
Predicting the R/S absolute configuration in asymmetric bifunctional catalysis (ABC)
Lin, Yun-Ming,Li, Zhongtao,Boucau, Julie
, p. 5275 - 5278 (2007)
A predictive model for assigning the R/S absolute configuration in chiral Lewis base-dependent asymmetric bifunctional catalysis (ABC) has been developed. Chiral Lewis base (LB*)-dependent ABC abolishes the chiral Lewis acid (LA*) co
Highly Syndiotactic or Isotactic Polyhydroxyalkanoates by Ligand-Controlled Yttrium-Catalyzed Stereoselective Ring-Opening Polymerization of Functional Racemic β-Lactones
Ligny, Romain,H?nninen, Mikko M.,Guillaume, Sophie M.,Carpentier, Jean-Fran?ois
supporting information, p. 10388 - 10393 (2017/08/22)
Reported herein is the first stereoselective controlled ROP of a specific family of racemic functional β-lactones, namely 4-alkoxymethylene-β-propiolactones (BPLORs). This process is catalyzed by an yttrium complex stabilized by a nonchiral tetradentate amino alkoxy bisphenolate ligand {ONOOR′2}2?, which features both a good activity and a high degree of control over the molar masses of the resulting functional poly(3-hydroxyalkanoate)s. A simple modification of the R′ substituents in ortho and para position on the ligand platform allows for a complete reversal from virtually pure syndioselectivity (Ps up to 0.91 with R′=cumyl) to very high isoselectivity (Pi up to 0.93 with R′=Cl), as supported by DFT insights. This is the first example of a highly isoselective ROP of a racemic chiral β-lactone.
Cinchona Alkaloid-Lewis Acid Catalyst Systems for Enantioselective Ketene-Aldehyde Cycloadditions
Zhu, Cheng,Shen, Xiaoqiang,Nelson, Scott G.
, p. 5352 - 5353 (2007/10/03)
Asymmetric cinchona alkaloid-catalyzed acid chloride-aldehyde cyclocondensation (AAC) reactions afford enantioenriched 4-substituted and 3,4-disubstituted β-lactones with near perfect absolute and relative stereocontrol. These reactions are characterized
C2-Symmetric Cu(II) Complexes as Chiral Lewis Acids. Catalytic, Enantioselective Cycloadditions of Silyl Ketenes
Evans, David A.,Janey, Jacob M.
, p. 2125 - 2128 (2007/10/03)
(matrix presented) C2-Symmetric bis(oxazoline)-Cu(II) complexes (4a-g) catalyze the enantioselective [2 + 2] cycloaddition between (silyl)ketenes and chelating carbonyl substrates. A range of substituted β-lactones can be produced in excellent yields and selectivities. It was also found that (trimethylsilyl)-ketene (1) may also undergo a highly selective hetero Diels-Alder reaction with β,γ-unsaturated α-keto esters.
