Baeyer−Villiger Oxidation of an Optically Active 1,4-Polyketone

Baeyer−Villiger oxidation of poly(S)-2-methyl-1-oxopropane-1,3-diyl (1) with m-chloroperbenzoic acid provided poly(ketone/ester) (2) in a ratio of ketone/ester = 82/18 in 73% isolated yield. Methanolysis of 2 (Mn = 8600) gave only a trace amount of methyl 3-hydroxybutyrate (5) which resulted from neighboring two ester units, −OCH(CH3)CH2C(O)2−. The major product was oligoketone (Mn = 650). A low yield of 5 indicates that an ester unit likely exists to distribute randomly in 2 rather than to form a block copolymer of a polyketone and a polyester.