Amines Bearing Tertiary Substituents by Tandem Enantioselective Carbolithiation–Rearrangement of Vinylureas

• Published in: Organic letters Vol. 15; no. 1; pp. 34 - 37
• Main Authors: Tait, Michael, Donnard, Morgan, Minassi, Alberto, Lefranc, Julien, Bechi, Beatrice, Carbone, Giorgio, O’Brien, Peter, Clayden, Jonathan
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 04-01-2013
• Subjects: Amines - chemistry; Catalysis; Lithium - chemistry; Molecular Structure; Sparteine - analogs & derivatives; Sparteine - chemistry; Stereoisomerism; Urea - chemistry; Vinyl Compounds - chemistry
• ISSN: 1523-7060; 1523-7052
• DOI: 10.1021/ol3029324

In the presence of (−)-sparteine or a (+)-sparteine surrogate, organolithiums add to N-alkenyl-N′-arylureas to give benzylic organolithiums in an enantioselective manner. Under the influence of DMPU, these organolithiums undergo rearrangement with migration of the N′-aryl ring from N to C, leading to the urea derivatives of enantiomerically enriched amines bearing tertiary substituents. Basic hydrolysis returns the functionalized amine, providing a new synthetic route to compounds with quaternary stereogenic centers bearing nitrogen.