Anti Selective Asymmetric Nitro Michael Reaction of Furanones: Diastereocontrol by Catalyst.
Catalyst controlled switching of diastereoselectivity from high syn selectivity >98/2 dr, syn) to anti selectivity (up to 96/4 dr, anti) of the asymmetric nitro Michael reaction of furanones is described. Anti diastereoselectivity of the nitro Michael reaction is very rare. With 0.1 5 mol loadings of an epi quinine catalyst, the reaction of 5 substituted 2(3H) furanones with nitroalkenes smoothly proceeded to give the anti Michael adducts in good yields (up to 95% with excellent diastereo and enantioselectivities (up to 96/4 dr, anti; up to 99% ee) DFT calculations support a model that accounts the high anti diastereoselectivity.
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