Polymerization of alkyl diazoacetates initiated by the amidinate/Pd system: efficient synthesis of high molecular weight poly(alkoxycarbonylmethylene)s with moderate stereoregularity

The initiating ability of a new system, amidinate/Pd, for the polymerization of diazoacetates is described. The system is effective in affording relatively high number-average molecular weight (Mn) polymers from ethyl diazoacetate (EDA, e.g., Mn = 45 100, 44% yield) and methyl diazoacetate (MDA, e.g., Mn = 26 200, 56% yield) in moderate yield. The polymerization of n-hexyl diazoacetate (nHDA) and benzyl diazoacetate (BDA) by the amidinate/Pd system yields high Mn polymers (Mn = ca.100 000), although the yield was below 10%. The system is also effective in the copolymerization of EDA with nHDA, BDA, and cyclohexyldiazoacetate (cHDA), affording high Mn copolymers in moderate yield. NMR spectra of the products obtained with the system suggest that the polymerization proceeds with significantly higher stereoregularity compared to that with previously reported Pd-based initiating systems.