Synthesis of Diverse β,β‐Diaryl β‐Siloxy Diamines and Application as Organocatalysts

β,β-Diaryl-β-siloxy diamines are developed as diverse diamine organocatalysts. The synthetic methodology enables structural diversification through Grignard reactions, as well as subsequent silylation and amination. These diamines catalyzed enantioselective fluorination of β-diketones in water with improved enantioselectivity (up to 53% ee) compared to conventional catalysts.

β,β-Diaryl-β-siloxy diamines are developed as a tunable scaffold for structurally diverse diamine-based organocatalysts. Synthesis is initiated with the reaction of an oxazolidine methyl ester from L-serine with various Grignard reagents, introducing a wide range of diaryl substituents at the β-position. By adjusting the reaction sequence of the silylation and amination steps, the developed synthetic approach enables the incorporation of diverse aryl, silyl, and amine groups, including cyclic, acyclic tertiary, and secondary amines, into 1,2-diamines. The resulting diamines are evaluated as catalysts in the enantioselective fluorination of β-diketones in water using N-fluorobenzenesulfonimide. Although the yield is similar to that of the conventional catalyst C1, the enantioselectivity is improved, reaching up to 53% ee.

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