A series of end-functionalized poly(9,9'-di-n-octylfluorene vinylene)s (EF-PFVs) with different end groups were obtained by 1) synthesizing EF-PFV with vinyl end groups by acyclic diene metathesis (ADMET) polymerization with a molybdenum catalyst and termination with an aldehyde and 2) subsequent olefin metathesis of the vinyl group with the molybdenum catalyst followed by Wittig-type coupling with another aldehyde. The exclusive formation of EF-PFVs containing a vinyl end group by the ADMET polymerization was confirmed by grafting PEG, and by the synthesis of amphiphilic triblock copolymers by combining atom transfer radical polymerization from the PFV chain end with PEG grafting through a click reaction. Various EF-PFVs with different end groups, such as C F , pyridyl, ferrocenyl, and terthiophene, have thus been prepared. Their fluorescence spectra (e.g., intensities, emission wavelengths) were influenced by the end groups and the length of the conjugation.

As eries of end-functionalized poly(9,9'-di-n-octylfluorene vinylene)s (EF-PFVs) with different end groups were obtained by 1) synthesizing EF-PFV with vinyl end groups by acyclic diene metathesis (ADMET) polymerization with am olybdenum catalyst and termination with an aldehyde and 2) subsequent olefin metathesis of the vinyl group with the molybdenum catalyst followed by Wittig-type coupling with another aldehyde.T he exclusive formation of EF-PFVs containing av inyl end group by the ADMET polymerization was confirmed by grafting PEG,a nd by the synthesis of amphiphilic triblock copolymers by combining atom transfer radical polymerization from the PFV chain end with PEG grafting through ac lick reaction. Various EF-PFVs with different end groups,s uch as C 6 F 5 ,p yridyl, ferrocenyl, and terthiophene,h ave thus been prepared. Their fluorescence spectra (e.g., intensities,emission wavelengths) were influenced by the end groups and the length of the conjugation.Conjugated polymers,s uch as poly(para-phenylene), polyfluorene,p oly(para-arylene vinylene)s,a nd polythiophene, are promising organic materials applied in optoelectronic and electrochemical devices. [1,2] Theprecise,efficient synthesis of defect-free (regular structures,c hemically pure) end-functionalized conjugated polymers has attracted considerable attention, not only for improving device performance, [2] but also because of the unique (optical and/or electronic) properties that result from the end modification (e.g., by energy transfer), as recently demonstrated for polyfluorenes containing discrete end groups,s uch as triarylamines,p erylene monoimide dyes,o rh eteroaryl moieties, [3][4][5] and poly(9,9dialkylfluorene-2,7-vinylene)s (PFVs). [6,7] It has been demonstrated that syntheses by acyclic diene metathesis (ADMET) polymerization [6][7][8][9][10][11] afford defect-free (without halogen/sulfur impurities,r egio-or stereoirregularity,orcross-linking etc.)PFVs, [6][7][8] poly(2,5-dialkylphenylene-1,4-vinylene)s, [9] and poly(N-alkylcarbazole-2,7-vinylene)s [8b] that display better properties than those prepared by conventional condensation (e.g., dehalogenation-condensation, Gilch reaction) methods.M oreover,e xclusive end functionalization can be achieved by treating the vinyl end groups in the resultant polymers prepared with ar uthenium carbene catalyst [6, 8b, 9] with Mo(CHCMe 2 Ph)(N-2,6-Me 2 C 6 H 3 )[OC-(CH 3 )(CF 3 ) 2 ]( "Mo catalyst") followed by Wittig-type coupling with an aldehyde. [12,13] One-pot approaches for combined ADMET polymerization and subsequent end functionalization with Ru [7a] and Mo [7b] catalysts have also recently been established. These methods,h owever,o nly provide synthetic means to introduce the same functional groups at the PFV chain ends,and precise methods for the synthesis of well-defined poly(arylene vinylene)s containing different end groups have been limited thus far.W eh erein report that different end groups can be introduced at PFV chain ends by combining ADMET polymerization with the Mo catalys...

…m it verschiedenen Endgruppen wird von K. Nomura et al. in der Zuschrift auf S. 5372 ff.b eschrieben. Die endfunktionalisierten Poly(9,9'-dialkylfluorenvinylen)-Derivate (EF-PFVs) wurden durch 1) die Synthese von EF-PFVs mit Vinyl-Enden durch Molybdän-katalysierte acyclische Dienmetathese und Te rminierung mit einem Aldehyd und 2) anschließende Olefin-Metathese mit einer Vinyl-Einheit sowie Wittig-Kupplung mit einem weiteren Aldehyd erhalten.

An efficient synthesis of both enantiomers of lycoperdic acid, a 4-hydroxyglutamic acid derivative from edible mushroom Lycoperdon perlatum, was achieved from a chiral aminoalcohol. The key steps were a stereoselective introduction of a C3 unit into a bicyclic ketone and oxidative cleavage of a cyclic vicinal diol into a dicarboxylic acid. This report provides the first synthesis of (−)-lycoperdic acid.

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