Development of Chiral Ureates as Chiral Strong Brønsted Base Catalysts

Recently, chiral Brønsted bases
having high basicity have
emerged as a powerful tool in developing new catalytic enantioselective
reactions. However, such chiral strong Brønsted base catalysts
are still very scarce. Herein, we report the development of a chiral
anionic Brønsted base having a N,N′-dialkyl ureate moiety as a basic site. Its prominent catalytic activity
was demonstrated in the enantioselective addition reactions of α-thioacetamides
as less acidic pronucleophiles with various electrophiles. Thus, the
newly developed chiral catalyst with high accessibility and structural
tunability would expand the scope of viable enantioselective transformations
under Brønsted base catalysis.