Living Anionic Addition Reaction of 1,1-Diphenylethylene Derivatives: One-Pot Synthesis of ABC-type Chain-End Sequence-Controlled Polymers

Abstract

In this study, a 1:1 addition reaction using 1,1-diphenylethylene (DPE) derivatives, referred to as the "living anionic addition reaction", was established to regulate the sequence of vinyl compounds having negligible homopolymerizability. The stoichiometric and successive addition reaction between a DPE anion and more reactive DPE derivatives proceeded quantitatively when the electrophilicity of the DPE derivatives was sufficiently enhanced by electron-withdrawing groups such as (trimethylsilyl)ethynyl and acyl groups. The relative electrophilicity of the DPE derivatives was predicted by Hammett's law and the β-carbon chemical shifts of the carbon−carbon double bonds. AB-and ABC-type chain-end sequence-controlled polystyrenes with well-defined structures were synthesized by reacting two or three DPE derivatives with difunctional anionic living polystyrene in increasing order of their electrophilicity in a one-pot reaction.

Synthesis of a Hierarchically Branched Dendritic Polymer Possessing Multiple Dendrons on a Dendrimer-like Backbone

“…58,59 Nonetheless, DPE derivatives usually cannot dimerize or homopolymerize due to steric hindrance, 60,61 unless pairs of DPE derivatives with, respectively, electron-pulling and pushing substituents were used. 62 Arm-1 and Arm-2 were From the NMR spectrum in Figure 1d, it is clear that the integration ratio of signals of protons f, g, and h is 1.27:2.12:1.00, which indicates that the ratio of the number of BSt and DPE-OSiBuMe 2 is ca. 2:1.…”

“…For BSt, the styrenic double bond was selectively polymerized while butenyl remained unreacted, yielding a living oligomer, sec -Bu-(BSt) m Li ( m = 1–4). DPE-OSiBuMe 2 underwent one-step efficient addition to the living oligomer due to the easy formation of the resulting carbanion that is stabilized by conjugation of the two phenyl rings. , Nonetheless, DPE derivatives usually cannot dimerize or homopolymerize due to steric hindrance, , unless pairs of DPE derivatives with, respectively, electron-pulling and pushing substituents were used . Arm-1 and Arm-2 were prepared under identical conditions but different batches with a feed molar ratio of sec -BuLi:BSt:DPE-OSiBuMe 2 :St ≈ 1:2:1:75.…”

Synthesis of Linear and Cyclic Discrete Oligomers with Defined Sequences via Efficient Anionic Coupling Reaction

“…72−84 Very recently, a trimer with exact ABC sequence was prepared through successive unidirectional addition of DPE derivatives possessing finely tuned electronic effects of the substituents on the phenyl rings. 85 In the present study, we develop a new strategy for the synthesis of sequence-defined discrete oligomers with exact uniform molecular weights through divergent chain growth using DPE-derived monomers. The homemade monomers possess a DPE head, a (protected) functional group, and a protected alkylhalide tail.…”

Anionic Self-alternating Polymerization of 1-(4-Vinylphenyl)-1-phenylethylene

“…In anionic polymerization, the non-homopolymerizability of 1,1-diphenyldethylene (DPE) derivatives has been widely exploited for quantitative chain-end functionalization of various groups for application as precursors in specially designed polymeric structures. − In-chain functionalization is also possible by utilizing the reactivity of DPE derivatives, as well as the usual α- and ω-functionalization. The DPE derivatives exclusively underwent 1:1 addition with various nucleophilic carbanions and formed the corresponding π-stabilized DPE carbanion without further propagation.…”