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-chloro-perbenzoic acid provided poly(ketone/ester) (2) in a ratio of ketone/ester = 82/18 in 73% isolated yield. Methanolysis of 2 (M-n = 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 (M-n = 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.