Thiourea Catalysis In Organic Synthesis
Robinson, David M.
MetadataShow full item record
A searchable Bento database containing 138 articles on thiourea organocatalysis was created. This database contains eight searchable fields, as well as a link to the article’s pdf file and an image of the representative reaction. The database focuses on why the author deemed the active thiourea catalyst to be the best catalyst, and how prevalent was the inclusion of 3,5‐bis(trifluoromethyl)aniline in the thiourea moiety. Over 70% of the articles reviewed contained a 3,5‐bis(trifluoromethyl)aniline substituent in the active catalyst. This substituent was used due to it being deemed as providing the strongest hydrogen bonds and making the N‐H proton more acidic. A series of 1D nOe Difference experiments were carried out to show that the O‐NH structural motif is more acidic than the privileged 3,5‐ bis(trifluoromethyl)aniline substituent, and that the O‐NH thiourea forms hydrogen bonds more readily. An intramolecular process of relaxation between the O‐NH proton and residual H20 was observed and provided conclusive evidence that the O‐NH thiourea hydrogen bonds more readily. The results have exciting potential for the future of organocatalysis, due to the O‐NH thiourea performing better than the privileged aniline derivative. Further studies utilizing thiourea organocatalysts can now use this improved substituent or continue to search for and develop even better ones.