Straightforward N-alkylation of diketopyrrolopyrroles through the Mitsunobu reaction with benzyl, α-branched, and chiral alcohols

Abstract

The N-alkylation of diketopyrrolopyrroles (DPPs) represents a fundamental step to ensure solubility and further processability. Commonly used nucleophilic subtitution on halogenated derivatives is replaced in this work by Mitsunobu reaction...

Chiral diketopyrrolopyrrole dyes showing light emission in solid and aggregate states

“…Starting from bis( p -bromophenyl)DPP ( 1 ) that was synthesized according to a previously reported procedure, 34 the two enantiomers of the corresponding bis-( N-sec -phenethyl)-DPP ( 2 RR and 2 SS ) were obtained through the newly reported enantioselective protocol based on the Mitsunobu reaction with enantiopure 1-phenylethanol reagents. 38 The chiral TPE-DPP derivatives ( 3 ) were finally obtained by Suzuki–Miyaura coupling between 2 and pinacol 1,2,2-triphenylethenylboronate ( TPE-Bpin ). 34 A thienyl analogue of TPE-DPP was also synthesized starting from the commercially available bis(2-bromothien-5-yl)DPP ( 4 ) pigment that was enantioselectively N -functionalized with sec -phenethyl groups yielding soluble 5 SS and 5 RR dyes.…”

Self‐assembly of chiral diketopyrrolopyrrole chromophores giving supramolecular chains in monolayers and twisted microtapes

“…Alternative functionalization along the aryl backbone through the Knoevenagel condensation reaction with amide and semicarbazone motifs has been described for ThDPP ‐based systems 55–58 . With regard to chirality, alkyl, amide, and amino acid side chains have been typically introduced through N‐ alkylation at the lactam 59–64 . Additionally, end capping of the aryl system to give axially chiral systems with promising circularly polarized luminescence (CPL) properties has been detailed 65–68 .…”

Tuning the photophysical and chiroptical properties of [4]helicene‐diketopyrrolopyrroles

“…29 Recently, other types of N-derivatization have also been developed, allowing for the introduction of aryl, 30,31 cleavable tert-butoxycarbonyl, [32][33][34] and, especially, chiral α-branched benzyl-type groups. 35 In order to develop chiral DPP derivatives, stereogenic functions can thus either be introduced at the N-position as chiral substituents or by carefully choosing stereogenic aromatic flanking groups. Accordingly, DPPs N-functionalized with chiral chains such as dihydrocitronellyl 36 and caproamides of chiral amines 37 have been reported and described as CD (circular dichroism) active upon aggregation, which indicates adoption of preferential chiral conformations and increased chiral supramolecular organization.…”

“…For this purpose, N ‐alkyl chains are commonly introduced via a bimolecular nucleophilic substitution reaction between the corresponding alkyl halide and the deprotonated lactams 29 . Recently, other types of N ‐derivatization have also been developed, allowing for the introduction of aryl, 30,31 cleavable tert ‐butoxycarbonyl, 32–34 and, especially, chiral α‐branched benzyl‐type groups 35 …”