CpTiCl2 -Catalyzed Cross-Coupling between Internal Alkynes and Ketones: A Novel Concept in the Synthesis of Halogenated, Conjugated Dienes.
Esther Roldan-MolinaMaria M NievasJorge A R NavarroJ Enrique OltraPublished in: Chemistry (Weinheim an der Bergstrasse, Germany) (2020)
A novel concept for the synthesis of halogenated, conjugated dienes is disclosed: the CpTiCl2 -catalyzed coupling of keto-alkynes, in the presence of Me3 SiBr/Et3 N⋅HBr. This reaction provided five-, six-, and seven-membered carbocycles, nitrogenated heterocycles, as well as six-membered oxygenated heterocycles leading to a brominated conjugate diene. These products showed high reactivity in the Diels-Alder, Suzuki, and Sonogashira reactions, giving complex chemical structures in only three steps from the corresponding acyclic keto-alkyne. Hopefully, this strategy will pave the way towards the synthesis of bioactive natural products and new materials.