POS1-0564
Synthesis of sequence-controlled oligomers using living anionic addition reaction of 1,1-diphenylethylene derivatives possessing protected formyl groups
When and Where
Nov 30, -0001
12:00am - 12:00am
Presenter(s)
Tomono Arichika (Institute of Science Tokyo)
Co-Author(s)
Abstract
1,1-Diphenylethylene (DPE) and its derivatives exhibit extremely low homopolymerizability owing to steric hindrance and low ceiling temperatures. It is well-known that the reaction of DPE with potassium naphthalenide (K-Naph) yields a DPE dimer dianion (AA-type dianion) via single-electron transfer and the sebsequent radical coupling. Although DPE anions do not undergo a further addition reaction with DPE itself, they can undergo a 1:1 addition reaction with more reactive DPE derivatives carrying electron-withdrawing groups (B) to give BAAB-type sequential tetramers. Furthermore, because the resulting DPE anions retain their living activity, terminal vinyl groups can be quantitatively introduced to both ends of the oligomer by termination with the vinyl-functionalized alkyl halides. This living anionic addition reaction using K-Naph allows the facile synthesis of highly symmetrical, defect-free BAAB-type DPE oligomers. However, the sequence order is dictated by the relative electrophilicity of the DPE derivatives, and the formation of homosequence (-AA) or reversed (-BA) unit is inherently restricted.
In this study, we focus on the DPE derivative (F: 4,4’-diformyl-1,1-diphenylethylene) possessing two reactive formyl groups on the framework. The formyl groups of F were converted to weakly electron-donating N,N'-dimethylimidazolidyl (F’) or electron-withdrawing N-tert-butylimino groups (F”) to modify the reactivity. The living anionic addition reaction of two protected DPE derivatives, F’ and F”, with K-Naph proceeded to give a sequence-controlled F”F’F’F” tetramer and a subsequent acidic deprotection reaction afforded the FFFF tetramer possessing AA homosequence in the repeating unit. This approach successfully affords the formyl-functionalized, sequence-controlled oligomers which are inaccessible via the conventional synthetic procedures.
In this study, we focus on the DPE derivative (F: 4,4’-diformyl-1,1-diphenylethylene) possessing two reactive formyl groups on the framework. The formyl groups of F were converted to weakly electron-donating N,N'-dimethylimidazolidyl (F’) or electron-withdrawing N-tert-butylimino groups (F”) to modify the reactivity. The living anionic addition reaction of two protected DPE derivatives, F’ and F”, with K-Naph proceeded to give a sequence-controlled F”F’F’F” tetramer and a subsequent acidic deprotection reaction afforded the FFFF tetramer possessing AA homosequence in the repeating unit. This approach successfully affords the formyl-functionalized, sequence-controlled oligomers which are inaccessible via the conventional synthetic procedures.
