Positive Effect of Water in Asymmetric Direct Aldol Reactions with Primary Amine Organocatalyst: Experimental and Computational Studies.

The origin of higher reactivity in water-accelerated asymmetric aldol reactions with our designed primary amine organocatalyst was elucidated by both computational and experimental methods. As suggested by the calculated transition-state structures for water-promoted imine-enamine isomerization, anti-selective aldol reaction and hemiaminal formation, the rate of this aldol reaction was found experimentally to be even more accelerated by the addition of cis-2-butene-1,4-diol as additive.