The results described herein demonstrate how the very mild reaction conditions of the Co(I)-catalyzed photochemical [2 + 2 + 2] cyclocotrimerization are suited to prepare chiral compounds containing unsubstituted and polysubstituted 2-pyridyl moieties starting from chiral nitriles without any detectable loss of enantiomerical purity. This further increases the already very broad synthetic scope of
Enantioselective Synthesis of α-Heteroarylpyrrolidines by Copper-Catalyzed 1,3-Dipolar Cycloaddition of α-Silylimines
作者:Ana Pascual-Escudero、María González-Esguevillas、Silvia Padilla、Javier Adrio、Juan C. Carretero
DOI:10.1021/ol5007373
日期:2014.4.18
α-Heteroarylpyrrolidines have been efficiently prepared via 1,3-dipolarcycloaddition between silylimines and activated olefins. In the presence of Cu(CH3CN)4PF6/Walphos as catalytic system, high levels of enantioselectivity (up to ≥99% ee) and diastereoselectivity were achieved (major formation of C-2/C-4 trans-substituted pyrrolidines). The reaction is compatible with a broad variety of dipolarophiles