Enantioselective Synthesis of Cyclopentanes by Phosphine-Catalyzed β,γ-Annulation of Allenoates
Chenxi Zhang1, Jeremy T Maddigan-Wyatt1, Xuan Nguyen1
1School of Chemistry, Monash University, Clayton 3800, Victoria, Australia.
Abstract:
Herein, we report the enantioselective phosphine-catalyzed β,γ-annulation of electron-poor allenes with bifunctional malonates. The reaction exploits a 2C phosphonium synthon that when accessed using (R)-SITCP gives 23 cyclopentanes with high stereoselectivity (most >95:5 er and >9:1 dr) and yield. In addition to the (3+2) annulation, a one-pot three-component variant to give the same cyclopentanes and a (3+2) annulation/Dieckmann cyclization cascade, along with mechanistic studies, are reported.
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