Organocatalytic 'difficult' michael reaction of ketones with nitrodienes utilizing a primary amine-thiourea based on Di-tert-butyl aspartate

摘要

The primary amine-thiourea based on di-tert-butyl (S)-aspartate and (1R,2R)-1,2-diphenylethylene-1,2-diamine has been successfully employed in the "difficult" Michael reaction between aromatic ketones or acetone with nitrodienes. The high stability and reactivity of the catalyst led to improved reaction conditions. Thus, the desired products were obtained in high to excellent yields (up to 100%) and excellent enantioselectivities (up to 99%) even at elevated temperatures. The combination of (1R,2R)-1,2-diphenylethylene- 1,2-diamine and di-tert-butyl (S)-aspartate provided an excellent thiourea organocatalyst for the "difficult" Michael reaction between methyl ketones and nitrodienes.