17250-77-0Relevant academic research and scientific papers
Control of transient aluminum-aminals for masking and unmasking reactive carbonyl groups
Barrios, Francis J.,Springer, Brannon C.,Colby, David A.
supporting information, p. 3082 - 3085 (2013/07/26)
A new reagent, the dimethylaluminum N,O-dimethylhydroxylamine complex, is effective at masking reactive carbonyl groups in situ from nucleophilic addition. This reagent allows chemoselective addition of reducing reagents, Grignard reagents, organolithiums, Wittig reagents, and enolates into substrates with multiple carbonyl groups. Moreover, the trapped carbonyl group, a stable aminal, can be unmasked in situ for additional synthetic manipulations.
Synthesis of enantiopure homo and copolymers by raft polymerization and investigation of their enantioselective lipase-catalyzed esterification
Yeniad, Bahar,Koekluekaya, N. Oruc,Naik, Hemantkumar,Fijten, M. W. Martin,Koning, Cor E.,Heise, Andreas
, p. 84 - 93 (2013/01/16)
Homo and copolymers were synthesized from enantionpure (R)- and (S)-1-(4-vinylphenyl)ethanol by reversible addition-fragmentation chain transfer polymerization. The polymerization conditions were optimized resulting in dioxane as the preferred reaction solvent. First-order polymerization kinetics and well-defined enantiopure homopolymers with low dispersities were obtained. In agreement with their enantiomeric composition, the (R) and (S)-polymers gave opposite optical rotation of light. Polymer analogous esterification of the chiral hydroxy groups catalyzed by enantioselective Candida antarctica Lipase B was strongly (R)-selective. Esterification on the homopolymer and copolymers could be achieved to a maximum of around 50 %.
Photochemical behavior of cyclopropyl-substituted benzophenones and valerophenones
Creary, Xavier,Hinckley, Jenifer,Kraft, Casey,Genereux, Madeleine
experimental part, p. 2062 - 2071 (2011/05/28)
p-Cyclopropylbenzophenone, 20, gives no photoreduction when irradiated in i-PrOH solvent. This is a general phenomenon and a number of cyclopropyl-substituted benzophenones, including 4-(endo-6-bicyclo[3.1.0]hexyl) benzophenone, 19, 4-(cis-2,3-dimethylcyclopropyl)benzophenone, 21, 4-(cis-2-vinylcyclopropyl)benzophenone, 22, and 4-(endo-7-bicyclo[4.1.0]hept-2- enyl)benzophenone, 23, also fail to undergo photoreduction. Instead these latter compounds undergo cis-trans isomerization when irradiated. A mechanism involving formation of an (n, π*) triplet, which subsequently fragments the strained cyclopropane bond to give a lower energy and unreactive open triplet, has been suggested. p-Cyclopropylvalerophenone, 25, and p-(endo-6-bicyclo[3.1.0]hexyl)valerophenone, 24, also undergo photoisomerization and fail to undergo the Norrish Type II photoreactions. Triplet energy dissipation by fragmentation of the cyclopropane bond is also proposed. In addition to the Norrish Type II reaction, p-cyclobutylvalerophenone, 27, undergoes a photofragmentation to give ethylene and p-vinylvalerophenone, 60, by an energy dissipation mechanism involving a 1,4-biradical derived from cyclobutane bond fragmentation.
Enzyme-responsive materials: Chirality to program polymer reactivity
Duxbury, Christopher J.,Hilker, Iris,De Wildeman, Stefaan M. A.,Heise, Andreas
, p. 8452 - 8454 (2008/09/21)
(Figure Presented) A programmed response: Enzyme-responsive materials have been prepared from enzymatically synthesized, enantiomerically pure monomers. The extent of the material's response is encoded within its chiral makeup. This code can be effectively read out by ab enzymatic process, which leads to a change in the thermal properties of the material. The picture shows esterification of chiral alcohol groups on a polymer backbone (green) with vinyl acetate (red).
