InCl3/CyNH2 Cocatalyzed Carbocyclization Reaction: An Entry to α-Disubstituted exo-Methylene Cyclopentanes
摘要:
An efficient and cheap synthetic approach to functionalized exo-methylene cyclopentanes has been developed from alpha-disubstituted formyl-alkynes by merging amine catalysis with the indium activation of alkynes. We uncovered the crucial role of the amine cocatalyst and the development of a new cooperative catalytic system allowed the cyclization of a broad range of substrates. A mechanistic study was realized in order to rationalize the determining influence of the amine cocatalyst.
Combined InCl3- and Amine-Catalyzed Intramolecular Addition of α-Disubstituted Aldehydes onto Unactivated Alkynes
摘要:
The combination of enamine-type catalysis to the indium-catalyzed activation of alkynes allows the efficient preparation of functionalized cyclopentanes bearing a quaternary stereogenic center. A broad range of formylalkynyl derivatives has been prepared. The InCl3/(Cy)(i-Pr)NH system efficiently promotes the carbocyclization reaction of alpha-disubstituted aldehydes in good to excellent yields.