Features of the Baeyer—Villiger reaction in the case of a complex variously functionalized substrate

The reactions of (3 S ,4 RS )-1,3-dideoxy-3-[(2 Z )-4-methoxy-3-methyl-4-oxobut-2-en1-yl]-4- C -methyl-4,5- O -(1-methylethylidene)pent-2-ulose with MCPBA and trifluoroperacetic acid were studied. It was shown that 60% MCPBA in CH 2 Cl 2 at room temperature caused isomerization in the acetonide fragment of this compound, while no expected Baeyer—Villiger (B—V) reaction was observed at the methyl ketone. In the MCPBA—AcONa system, the epoxidation of the activated double bond followed the conjugate addition—elimination scheme. The oxidation with trifluoroperacetic acid occurred at the methyl ketone moiety with subsequent decomposition of the dioxolane protecting group and intramolecular lactonization. The introduction into the B—V reaction of the corresponding aldehyde-containing partner instead of the methyl ketone-containing ulose led to an abnormal product of furanization with the loss of the chiral center.