scholarly journals Helical Polycarbenes Bearing D-Prolinol Ester Pendants: An Efficient Catalyst for Asymmetric Michael Addition Reaction

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1369
Author(s):  
Na Liu ◽  
Xinyue Zhou ◽  
Li Zhou ◽  
Zongquan Wu
Keyword(s):  
Molecular Weight ◽  
Michael Addition ◽  
Addition Reaction ◽  
Significant Loss ◽  
Michael Addition Reaction ◽  
Controlled Polymerization ◽  
Efficient Catalyst ◽  
Molecular Weights ◽  
Asymmetric Michael Addition ◽  
The Michael Addition

a novel diazoacetate monomer (1) carrying tert-butyloxycarboryl (Boc) protected D-prolinol ester was designed and synthesized successfully. Molecular weight-controlled polymerization of 1 using the complex of π-allylPdCl coordinated Wei-phos (LR) ligand gives a series of helical polycarbenes (poly-1ms) with well-defined molecular weights (Mns) and low polydispersity (Mw/Mns). Removing the protecting Boc groups on the D-prolinol ester pendants leads to the formation of helical poly-1m-As, which showed high optical activity. Furthermore, the poly-1m-As showed high catalytic ability on asymmetric Michael addition reaction (up to 76% ee and 94/6 dr). Both the enantioselectivity and diastereoselectivity of the Michael addition reaction were increased comparing to D-prolinol as catalyst. Moreover, the helical polycarbene catalyst can be easily recovered and reused at least four times without significant loss of its enantioselectivity and diastereoselectivity.

Preparation of a microsized cerium chloride-based catalyst and its application in the Michael addition of β-diketones to vinyl ketones

2014 ◽  
Vol 38 (4) ◽  
pp. 1493-1502 ◽  
Author(s):  
Alexander O. Terent'ev ◽  
Vera A. Vil' ◽  
Ivan A. Yaremenko ◽  
Oleg V. Bityukov ◽  
Dmitri O. Levitsky ◽  
...  
Keyword(s):  
Michael Addition ◽  
Addition Reaction ◽  
Cerium Chloride ◽  
Michael Addition Reaction ◽  
Efficient Catalyst ◽  
The Michael Addition

A facile method was developed for the preparation of microsized cerium chloride, which is an efficient catalyst in the Michael addition reaction.

Novel Polyaspartic Ester Polyureas Based on Flexible Polyaspartic Ester

2011 ◽  
Vol 197-198 ◽  
pp. 1294-1298
Author(s):  
Ping Lu ◽  
Wei Bo Huang ◽  
Xue Qiang Ma ◽  
Xu Dong Liu
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Hydrogen Bonding ◽  
Molecular Weight Distribution ◽  
Michael Addition ◽  
Weight Distribution ◽  
Addition Reaction ◽  
Chain Extender ◽  
Michael Addition Reaction ◽  
Ft Ir

New polyaspartic ester (PAE) chain extender named PAE-f was prepared via two steps of Michael addition reactions:(1) Michael addition reaction between 4,4’-methylenebis(2-methyl cyclohexyl amine) (Laromin C260) and excessive dialkyl maleates（DEF）; (2) The Michael addition reaction of the residual dialkyl maleates of step (1) with polyester polyamine Jeffamine D230. The two-steps method proposed could reduce the reaction time in comparison with the current one step Michael addition reaction method, thus satisfying the industrialized production. New PAE based polyureas were synthesized by reacting the PAE-f chain extender with aliphatic polyisocyanates 4,4’-diisocyanato dicyclohexylmethane (H12MDI) / polyester polyamine Jeffamine D2000 prepolymer at room temperature. FT-IR and GPC were employed to characterize the new PAE prepared, and the morphology, molecular weight distribution and mechanical properties of the prepared PAE based polyureas were investigated by means of FT-IR and GPC. The FT-IR results indicated that the hydrogen bonding degree of amidogen groups in hard segments of the prepared polyureas were high, the length of hydrogen bonding were 0.305nm～0.306nm. The GPC experimental results show that the weight average molecular weight of the PAE-f based polyureas were 4.95×104～6.05×104,Mw/Mn were 1.65～1.97, the molecular weight distribution were relatively narrow. The mechanical properties demonstrated that the tensile strength were 14.7～22.5MPa, Elongation at break were 306～511%, Yang’s modulus were 67～127MPa, Shore A hardness were 64～83. The mechanical properties confirmed that the polyureas based on PAE-f were kinds of elastomeric materials with satisfied flexibility, strength, module and hardness.

Efficient Synthesis of 3-Amino-1,5-benzodiazepine-2-one Derivatives

Synlett ◽  
2017 ◽  
Vol 28 (10) ◽  
pp. 1183-1186 ◽  
Author(s):  
Nobuhiro Obara ◽  
Takeshi Watanabe ◽  
Tomohiro Asakawa ◽  
Toshiyuki Kan ◽  
Takao Tanaka
Keyword(s):  
Michael Addition ◽  
Convenient Method ◽  
Addition Reaction ◽  
Efficient Synthesis ◽  
Michael Addition Reaction ◽  
One Pot ◽  
Simple Method ◽  
The Michael Addition

A convenient method for synthesizing 3-amino-1,5-benzodiazepine-2-one via the Michael addition reaction of o-phenylenediamine with dehydroalanine ester derivatives, followed by cyclization, was developed. This simple method was used to obtain a variety of N-substituted 3-amino-1,5-benzodiazepine-2-ones in one pot with good yields.

Use of (R)-Mandelic Acid as Chiral Co-Catalyst in the Michael Addition Reaction Organocatalyzed by (1S,4S)-2-Tosyl-2,5-diazabicyclo[2.2.1]heptane under Solvent-Free Conditions

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
C. Gabriela Ávila-Ortiz ◽  
Manuel López-Ortiz ◽  
Alberto Vega-Peñaloza ◽  
Ignacio Regla ◽  
Eusebio Juaristi
Keyword(s):  
Michael Addition ◽  
Mandelic Acid ◽  
Addition Reaction ◽  
Solvent Free ◽  
Reaction Intermediates ◽  
Michael Addition Reaction ◽  
Co Catalyst ◽  
Co Catalysts ◽  
Solvent Free Conditions ◽  
The Michael Addition

AbstractThis article describes a study on the Michael addition reaction of cyclohexanone to nitroolefins catalyzed by the chiral secondary amine (1S,4S)-2-tosyl- 2,5-diazabicyclo[2.2.1]heptane. Reactions were carried out under solvent-free conditions to make them more environmentally friendly. Initially, the observed diastereoand enantioselectivities were moderate to good, but were significantly improved by lowering the reaction temperature. Furthermore, a variety of chiral acids were also tested as co-catalysts in both of their enantiomeric forms, which revealed that (R)-mandelic acid affords excellent results in terms of yield and stereoselectivity. Monitoring the reaction by MS-TOF allowed for the detection of key reaction intermediates, and a reasonable reaction mechanism in which both catalysts are involved is proposed.

The design of a spiro-pyrrolidine organocatalyst and its application to catalytic asymmetric Michael addition for the construction of all-carbon quaternary centers

2015 ◽  
Vol 51 (49) ◽  
pp. 9979-9982 ◽  
Author(s):  
Jin-Miao Tian ◽  
Yong-Hai Yuan ◽  
Yong-Qiang Tu ◽  
Fu-Min Zhang ◽  
Xiao-Bo Zhang ◽  
...  
Keyword(s):  
Michael Addition ◽  
Addition Reaction ◽  
Silyl Ether ◽  
Michael Addition Reaction ◽  
Quaternary Centers ◽  
Asymmetric Michael Addition ◽  
Catalytic Asymmetric

A novel chiral spiro-pyrrolidine silyl ether organocatalyst has been designed and applied to an asymmetric Michael addition reaction.

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