ChemInform Abstract: Enantioselective Protonation in the Sulfa-Michael Addition Using Chiral Squaramides as Hydrogen-Bonding Organocatalysts.

ChemInform ◽  
2012 ◽  
Vol 43 (19) ◽  
pp. no-no
Author(s):  
Le Dai ◽  
Hongjun Yang ◽  
Jingze Niu ◽  
Fen-Er Chen
Keyword(s):  
Hydrogen Bonding ◽  
Michael Addition

Enantioselective Protonation in the Sulfa-Michael Addition Using Chiral Squaramides as Hydrogen-Bonding Organocatalysts

Synlett ◽  
2011 ◽  
Vol 2012 (02) ◽  
pp. 314-316 ◽  
Author(s):  
Fener Chen ◽  
Le Dai ◽  
Hongjun Yang ◽  
Jingze Niu
Keyword(s):  
Hydrogen Bonding ◽  
Michael Addition

ChemInform Abstract: Fast, Solvent-Free and Hydrogen-Bonding-Mediated Asymmetric Michael Addition in a Ball Mill.

ChemInform ◽  
2012 ◽  
Vol 43 (34) ◽  
pp. no-no
Author(s):  
Yi-Feng Wang ◽  
Ru-Xiang Chen ◽  
Ke Wang ◽  
Bin-Bin Zhang ◽  
Zhao-Bo Li ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Michael Addition ◽  
Ball Mill ◽  
Solvent Free ◽  
Asymmetric Michael Addition

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.

Novel ferrocene-based bifunctional amine–thioureas for asymmetric Michael addition of acetylacetone to nitroolefins

2015 ◽  
Vol 13 (17) ◽  
pp. 5054-5060 ◽  
Author(s):  
Xiaochen Ren ◽  
Chunyan He ◽  
Yingle Feng ◽  
Yonghai Chai ◽  
Wei Yao ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Efficient Method ◽  
Michael Addition ◽  
High Yield ◽  
Bifunctional Catalysts ◽  
Michael Adducts ◽  
Asymmetric Michael Addition ◽  
Multiple Hydrogen Bonding

An efficient method was developed to synthesize the ferrocene-based bifunctional amine–thioureas bearing multiple hydrogen-bonding donors. Asymmetric Michael addition of acetylacetone to nitroolefins catalyzed by these novel bifunctional catalysts affords the Michael adducts in high yield and moderate to excellent enantioselectivities.

Fast, solvent-free and hydrogen-bonding-mediated asymmetric Michael addition in a ball mill

2012 ◽  
Vol 14 (4) ◽  
pp. 893 ◽  
Author(s):  
Yi-Feng Wang ◽  
Ru-Xiang Chen ◽  
Ke Wang ◽  
Bin-Bin Zhang ◽  
Zhao-Bo Li ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Michael Addition ◽  
Ball Mill ◽  
Solvent Free ◽  
Asymmetric Michael Addition
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