862995-45-7Relevant articles and documents
N,N′-diarylureas: A new family of atropisomers exhibiting highly diastereoselective reactivity
Clayden, Jonathan,Turner, Hazel,Helliwell, Madeleine,Moir, Elizabeth
, p. 4415 - 4423 (2008/09/21)
(Chemical Equation Presented) 2,6-Disubstituted N-aryl ureas rotate slowly about their Ar-N bonds and can exist as separable atropisomers. They also react remarkably diastereoselectively, with the urea axis controlling new stereogenic centers with high fidelity in a variety of nucleophilic and electrophilic addition reactions. The sense of diastereoselectivity in lateral lithiation-electrophilic quench reactions is electrophile-dependent and appears to be the result of stereospecific reaction with one of two interconvertible diastereoisomeric organolithiums.
Ring-selective functionalization of N,N′-diarylureas by regioselective N-alkylation and directed ortho metalation
Clayden, Jonathan,Turner, Hazel,Pickworth, Mark,Adler, Thomas
, p. 3147 - 3150 (2007/10/03)
(Chemical Equation Presented) Unsymmetrical N,N′-diarylureas may be alkylated regioselectively at the more sterically congested nitrogen atom. The resulting mono-N-alkylated ureas undergo directed metalation (ortholithiation) with sec-BuLi to yield, on el
