"On Water" Direct Catalytic Vinylogous Aldol Reaction of Silyl Glyoxylates.

The unique reactivity of water in the direct catalytic vinylogous aldol reaction of silyl glyoxylates is reported. With the hydrogen-bonding networks from water, the unfavorable homogeneous reactions in organic solvents were severely suppressed, and the "on water" relay chemistry for the vinylogous aldol reaction was realized in heterogeneous conditions (water as solvent), providing the desired α-hydroxysilanes with a quaternary carbon center in high yields. Moreover, new insights on the role of water in biological systems were demonstrated.