Mechanism of the primary and secondary amine catalyzed thio-Michael addition reaction with (meth)acrylates

ORGN 168

Justin W. Chan, justin.chan@usm.edu1, Hui Zhou, hui.zhou@usm.edu1, Huanyu Wei, huanyuwei@gmail.com2, and Charles Hoyle, Charles.Hoyle@usm.edu3. (1) School of Polymers and High Performance Materials, The University of Southern Mississippi, 118 College Drive #10076, Hattiesburg, MS 39406, (2) School of Polymers and High Performance Materials, University of Southern Mississippi, 118 College Drive, Box 10076, Hattiesburg, MS 39406, (3) Department of Polymer Science, The University of Southern Mississippi, Box 10076, Southern Station, Hattiesburg, MS 39406
The thio-Michael reaction between a thiol and a (meth)acrylate proceeds rapidly using primary and secondary amines, and quite slowly with aliphatic tertiary amines. The kinetics have been evaluated in detail using real-time infrared analysis. Surprisingly, the rapid reaction catalyzed by primary and secondary amines is not directly dependent upon the basicity of the amine. By carrying out an extensive investigation of the effect of the amine structure on the polymerization rate, an initial nucleophilic attack by the amine followed by reaction of the subsequent intermediate with an aliphatic thiol is proposed to account for the unusually rapid thio-Michael addition afforded by primary and secondary amines. Based on the results for the amine catalysts, a more general mechanism for the overall catalysis of thio-Michael addition reactions will be discussed.
 

Physical Organic Chemistry, Combinatorial and Process Chemistry, New Reactions and Methodology, Peptides, Proteins and Amino Acids
8:00 PM-10:00 PM, Sunday, April 6, 2008 Morial Convention Center -- Hall A, Poster

Division of Organic Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008