A Baylis–Hillman/ozonolysis route towards (±) 4,5-dihydroxy-2,3-pentanedione (DPD) and analogues

The Baylis–Hillman reaction between 2-(tert-butyldimethylsilyloxy)ethanal and 3-buten-2-one followed by desilylation gave rise to the corresponding α-methylene-β,γ-dihydroxy ketone further converted by reductive ozonolysis of the carbon–carbon double bond into racemic 4,5-dihydroxy-2,3-pentanedione (DPD), a significant molecule in bacterial cell–cell communication systems. The same sequence applied to other substrates allowed the preparation of chain elongated analogues and 5-O-acylated derivatives of DPD.