Wang Q, Li T.-R, Lu L.-Q, * Li M.-M, Zhang K, Xiao W.-J. * Central China Normal University,
Hubei and Lanzhou University, P. R. of China
Catalytic Asymmetric [4 + 1] Annulation of Sulfur Ylides with Copper–Allenylidene
Intermediates.
J. Am. Chem. Soc. 2016;
138: 8360-8363
Key words
[4+1] annulation - sulfur ylides - copper catalysis - indolines
Significance
The authors report a copper-catalyzed asymmetric [4+1] cycloaddition by trapping copper–allenylidene
dipolar intermediates with sulfur ylides. A variety of chiral indolines were obtained
with high stereoselectivities (≤98% ee and dr > 95:5).
Comment
This reaction affords an opportunity for the ready synthesis of chiral indoline products
and related cycloadducts with high stereoselectivities. Mechanistic studies suggest
that this reaction is a sequential process that involves decarboxylative propargylation/SN2 reactions promoted by binuclear copper complexes.
