Synthesis of dendronized polymers through Pd-initiated C1 polymerization of diazoacetates with different generation ester-type dendron groups

Abstract

A series of diazoacetates with an ester-type dendron unit of 1^st to 3^rd generation as an ester substituent were newly prepared and their Pd-initiated polymerization was conducted to afford dendronized C1 polymers with the SEC-estimated number-average molecular weight (M_n,SEC) of up to 16 700 and a relatively narrow molecular weight distribution (Đ = 1.12–1.37). The glass transition temperature (T_g) of these dendronized polymers increased with the increasing generation of the dendron unit, where the degree of increase (ΔT_g) was much larger than that observed with their vinyl polymer counterparts (polymethacrylates with the same dendron substituents). The diazoacetate with the 3^rd 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.