Zur Stereochemie von Allenen, I. Darstellung und optische Spaltung einer Gruppe von Allencarbonsäuren

Kresze, G.; Runge, Wolfgang; Ruch, Ernst

doi:10.1002/jlac.19727560111

Cited by 64 publications

(12 citation statements)

References 17 publications

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“…1.3). 5 To a lesser extent, photolysis of dimers is also possible, although yields are low due to competing decarbonylation reactions 6. A more viable light (or heat) based method of ketene generation, one that has seen extensive use in synthetic chemistry, is the Wolff rearrangement.…”

Section: Introductionmentioning

confidence: 99%

Catalytic, asymmetric reactions of ketenes and ketene enolates

2009

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Section: Introductionmentioning

confidence: 99%

Catalytic, asymmetric reactions of ketenes and ketene enolates

2009

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“…EPK was synthesized according to the reported procedure6 and distilled prior to use under a reduced procedure. MBA was dried and distilled over CaH 2 .…”

Section: Methodsmentioning

confidence: 99%

Novel approach to well‐defined polyester by living anionic alternating copolymerization of ethylphenylketene with 4‐methoxybenzaldehyde

Nagai

Sudo

Sanda

et al. 2001

J. Polym. Sci. A Polym. Chem.

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A living anionic alternating copolymerization of ethylphenylketene (EPK) with 4-methoxybenzaldehyde (MBA) was achieved. When n-butyllithium was added to a mixture of EPK and MBA in tetrahydrofuran at Ϫ40°C in the presence of an excess amount of lithium chloride, the copolymerization of these monomers proceeded via complete 1:1 alternating manner to afford the polymer with a narrow molecular weight distribution. A linear relationship was observed between the molecular weight and the monomer/initiator ratio, keeping a narrow molecular weight distribution. The structure of the obtained polymer was determined to be a polyester by IR spectroscopy together with the reductive degradation of the polymer by lithium aluminum hydride, which quantitatively afforded the corresponding diol to the repeating unit of the expected polyester structure. Both conversions of EPK and MBA agreed to a first-order kinetic equation with linear evolution between the molecular weight and conversion. These observations along with the successful results in two-stage polymerization indicate that the present copolymerization proceeded through a living mechanism.

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“…EPK was synthesized according to the reported procedure 9 and was distilled before use under reduced pressure. BA was dried and distilled with CaH 2 before use.…”

Section: Materials and Instrumentsmentioning

confidence: 99%

Stereocontrolled anionic alternating copolymerization of ethylphenylketene with benzaldehyde by a bisoxazoline ligand

Nagai

Sudo

Endō

2004

J. Polym. Sci. A Polym. Chem.

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Anionic copolymerization of ethylphenylketene with benzaldehyde with butyllithium or diethylzinc as the initiator proceeded in a perfect 1:1 alternating manner to produce the corresponding polyester, whose repeating unit had two adjacent chiral centers. The relative stereochemistry between these two chiral centers was successfully controlled by the addition of (S,S)-(-)-2,2Ј-isopropylidenebis(4-tert-butyl-2oxazoline), producing the corresponding polyester that had excellent diastereoselectivity (erythro-configuration : threo-configuration ϭ 4:96). The diastereomeric ratio was determined by high-performance liquid chromatography analysis of the diol, which was obtained by reductive degradation of the polyester while maintaining the configuration of the repeating unit.

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Zur Stereochemie von Allenen, I. Darstellung und optische Spaltung einer Gruppe von Allencarbonsäuren

Cited by 64 publications

References 17 publications

Catalytic, asymmetric reactions of ketenes and ketene enolates

Catalytic, asymmetric reactions of ketenes and ketene enolates

Novel approach to well‐defined polyester by living anionic alternating copolymerization of ethylphenylketene with 4‐methoxybenzaldehyde

Stereocontrolled anionic alternating copolymerization of ethylphenylketene with benzaldehyde by a bisoxazoline ligand

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