α-Triethylsilyl-α-diazoacetone in double cross-aldolisation: convenient acetone equivalent toward 5-hydroxy-1,3-diketones

α-Triethylsilyl-α-diazoacetone underwent a sequential aldolisation–deprotection–aldolisation process to access the 2-diazo-3-oxo-1,5-dihydroxy skeleton with significant diversity. The diazo group could be efficiently removed by treatment with rhodium acetate to afford the corresponding 5-hydroxy-1,3-diketones.