Synthesis of Dendronized Polymers Through Pd-Initiated C1 Polymerization of Diazoacetates with Different Generation Ester-type Dendron Groups

A series of diazoacetates with an ester-type dendron unit of 1st to 3rd generation as an ester substituent were newly prepared and their Pd-initiated polymerization was conducted to afford dendronized C1 polymers with SEC-estimated number-average molecular weight (M_n,SEC) up to 16700 and a relatively narrow molecular weight distribution (Đ = 1.12–1.37). Glass transition temperature (T_g) of these dendronized polymers increased with the increasing generation of the dendron unit, where the degree of the increase (ΔT_g) was much larger than that observed with their vinyl polymer counterparts (polymethacrylates with the same dendron substituents). The diazoacetate with the 3rd generation dendron unit was successfully copolymerized with benzyl diazoacetate to afford a copolymer, whose dendron-derived units were converted to those with multiple hydroxy groups via deprotection of acetonide-protecting groups at the peripheral positions.