Asymmetric organocatalytic synthesis of β-Hydroxyynones with a quaternary carbon center under aqueous conditions

the chiral tertiary amine thiourea catalyzed direct aldol reaction of unmodified methyl ynones under aqueous conditions is described. this procedure avoided the retro-aldol reaction of the β-hydroxyynone products, and tolerated both the isatin (1h-indole-2,3-dione) and the less active acyclic α-keto esters as acceptors, affording a structurally diverse array of β-hydroxyynones bearing a quaternary carbon center with moderate to good yields and enantioselectivities.