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SYNTHESIS
Remarkable Complexity From One Pot
MAUREEN ROUHI
A new domino process transforms five components into a hexasubstituted benzene that resembles natural products with interesting biological activities. The process delivers seven chemical bonds and five elements of diversity from one pot.
Chemists Pierre Janvier and Jieping Zhu at the National Center for Scientific Research, Gif-sur-Yvette, France, and Hugues Bienaymé at Chrysalon, a start-up drug-discovery-support company based in Villeurbanne, France, accomplished this feat by developing conditions in which the three-component synthesis of an oxazole is compatible with two subsequent cycloaddition reactions [Angew. Chem. Int. Ed., 41, 4291 (2002)].
In domino processes, bond-forming transformations take place under the same reaction conditions, and subsequent transformations are the consequence of the functionality formed in the previous one. Domino processes are "attracting considerable attention because they enable rapid assembly of complex molecules in one pot," notes Albert Padwa, a chemistry professor at Emory University. The work of the French chemists "provides a very interesting example, where highly functionalized polyheterocycles can be prepared by a novel five-component domino process," he tells C&EN.
Simple to operate and giving good yields, the sequence Zhu and coworkers developed is highly adaptable to diversity-oriented parallel synthesis. They have prepared a range of polyheterocycles with three different amines, three aldehydes, one isocyanoacetamide, two pentafluorophenyl 3-arylprop-2-ynoates, and three dienophiles as starting materials. Yields range from 32 to 67%. |