Enantioselective Sulfur-<i>Michael</i>Addition of Thioacetic Acid to Nitroalkenes Catalyzed by Bifunctional Amine-Thiourea Catalysts
作者:Renchao Wang、Jiaxi Xu
DOI:10.1002/hlca.201400125
日期:2014.12
An enantioselectiveMichaeladdition of thioacetic acid (AcSH) to nitroalkenes, catalyzed by a leucine‐derived bifunctional aminethiourea, was developed with high yields and moderate enantioselectivities. The thiourea‐ammonium salt formed in the reaction is identified as the active catalyst, and the multiple H‐bonding system is responsible for the stereocontrol. The resulting thioester products are
Enantio- and diastereoselective addition of thioacetic acid to nitroalkenes via N-sulfinyl urea catalysis
作者:Kyle L. Kimmel、MaryAnn T. Robak、Stephen Thomas、Melissa Lee、Jonathan A. Ellman
DOI:10.1016/j.tet.2012.01.048
日期:2012.3
The enantioselective addition of thioacetic acid to nitroalkenes was achieved using N-sulfinyl urea catalysis. In this report, the scope of the reaction was extended to the enantio- and diastereoselective thioacetic acid addition to cyclic alpha,beta-disubstituted nitroalkenes. Additionally, the role of the sulfinyl group was investigated by replacing it with a variety of aryl and sulfonyl groups. Of 15 urea catalysts synthesized and tested, none displayed comparable selectivity to the sulfinyl catalysts, highlighting the importance of the sulfinyl group in attaining high enantioselectivity in the thioacetic acid addition. (C) 2012 Elsevier Ltd. All rights reserved.