Preparation of Ketals from 2,2-Dimethoxypropane<sup>1</sup>

Lorette, N. B.; Howard, William Lee

doi:10.1021/jo01074a010

Cited by 61 publications

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“…Aso, et a/., 5 used IR and 1 H NMR spectroscopies to detect small amounts of the formate group. However, its presence could not be detected in the 13 C NMR spectrum for…”

Section: Structure Of Poly( Divinyl Formal)mentioning

confidence: 95%

“…The use of appropriate model compounds is indispensable for the reliable assignment of the polymer 13 C NMR data. The 13 C NMR data of the following model compounds have been published: 1 ,3-dioxanes/ 9 formate, and acetates, 18 branched alkanes/ 0 cyclopentanes and cyclohexanes, 21 and vinyl ethers.2 2 The 13 C-NMR data of 1,3-dioxolanes were obtained by us and are summarized in Table II Polymer J., Vol.…”

Section: Structure Of Poly( Divinyl Formal)mentioning

confidence: 99%

“…acetone dimethyl acetal and ethylene chlorohydrin: bp 72-75°Cj3 mmHg (lit. 13 bp 75°Cj2 mmHg). This compound was dehydrochlorinated over KOH under slightly reduced pressure.…”

mentioning

confidence: 98%

“…Recently, it was shown that 13 C NMR spectroscopy was a very powerful tool for elucidation of the microstructure of several cyclopolymers. 10 • 11 Therefore, we carried out a detailed investigation of the 13 C NMR spectrum ofpoly(divinyl formal) and poly(divinyl acetal)s. The modes of propagation of divinyl formal and divinyl acetals which have been described in the literature are summarized in Schemes I, 2, and 3.…”

mentioning

confidence: 99%

“…10 • 11 Therefore, we carried out a detailed investigation of the 13 C NMR spectrum ofpoly(divinyl formal) and poly(divinyl acetal)s. The modes of propagation of divinyl formal and divinyl acetals which have been described in the literature are summarized in Schemes I, 2, and 3. These monomers will propagate via the uncyclized (I) and cyclized radicals (Scheme 1).…”

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confidence: 99%

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The Microstructure of Poly(divinyl acetal)s as Determined by 13C NMR Spectroscopy. Ring Stereochemistry and Isomerization Propagation

Tsukino

Kunitake

1979

Polym J

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ABSTRACT:Divinyl formal, acetaldehyde divinyl acetal, and acetone divinyl acetal were polymerized freeradically, and the polymer structures were determined by detailed analyses of 13 C NMR spectra. The carbon chemical shifts of various structures which might be formed by simple propagation, by cyclopolymerization, and by isomerization propagation were derived from those of a variety of model compounds and their combinations. All the polymers contained the cis-4,5-disubstituted-1 ,3-dioxolane ring as the predominant structural unit in the main chain (ca. 75%) and as the pendent group (ca. 25%). The latter structure was formed by hydrogen abstraction of the propagating methylenedioxolane radical from the neighboring methylene group. Similar hydrogen migration conceivably occurred also during the polymerization of diallylamines.KEY WORDS 13 C NMR Spectroscopy I Poly(divinyl formal) I Poly(divinyl acetal) I Cyclopolymerization I Steric Structure I Divinyl formal and divinyl acetals readily undergo radical cyclopolymerization. 1 -8 These polymers are partially cyclized and the cyclized structure may be composed of five-and/or six-membered rings (see Scheme I)?· 4 In addition, the formation of the isomerized and other structural units was reported in several cases. 5 -7 The polymer structure could be inferred also from the oligomer structure. 9 These structure determinations have been performed by chemical means (hydrolysis and the subsequent determination of the I ,2-glycol content), and by IR and 1 H NMR spectroscopies. However, the conclusions were not necessarily definitive, and the stereochemical information was totally nonexistent.Recently, it was shown that 13 C NMR spectroscopy was a very powerful tool for elucidation of the microstructure of several cyclopolymers. 10 • 11 Therefore, we carried out a detailed investigation of the 13 C NMR spectrum ofpoly(divinyl formal) and poly(divinyl acetal)s.

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“…Aso, et a/., 5 used IR and 1 H NMR spectroscopies to detect small amounts of the formate group. However, its presence could not be detected in the 13 C NMR spectrum for…”

Section: Structure Of Poly( Divinyl Formal)mentioning

confidence: 95%

Section: Structure Of Poly( Divinyl Formal)mentioning

confidence: 99%

“…acetone dimethyl acetal and ethylene chlorohydrin: bp 72-75°Cj3 mmHg (lit. 13 bp 75°Cj2 mmHg). This compound was dehydrochlorinated over KOH under slightly reduced pressure.…”

mentioning

confidence: 98%

mentioning

confidence: 99%

mentioning

confidence: 99%

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The Microstructure of Poly(divinyl acetal)s as Determined by 13C NMR Spectroscopy. Ring Stereochemistry and Isomerization Propagation

Tsukino

Kunitake

1979

Polym J

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Does the Anomeric Effect in Ketals Depend on the Hybridization of the Central Carbon Atom?

et al. 1998

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Enthalpies of formation ΔHf°(g) of ketals prepared from cyclopropanone, cyclobutanone, cyclopentanone, cyclohexanone, and 7‐norbornanone with methanol, ethylene glycol, and 2,2‐dimethyl‐1,3‐propanediol, as well as of acetals/ketals of acyclic aldehydes and ketones, have been determined by measuring their heats of combustion and their heats of sublimation/vaporization. Group increments defining the strain‐free energy level have been derived from the collected experimentally determined ΔHf°(g) values of unstrained acetals and ketals, and the anomeric stabilizations of these groups (given in brackets) have been calculated from a comparison of their group increments with those of ethers: CH2[2O, C] –64.9 (−20.2), CH[2O, C] –63.5 (−21.3), C[2O, 2C] –61.9 (−26.8), CH[2O, Ph] –58.4 (−16.2), C[2O, Ph, C] –56.3 (−21.2), C[2O, 2Ph] –67.1 (−32.0) kJ mol−1. Enthalpies of formation ΔHf°(g) of cyclic and spirobicyclic ketals have also been determined experimentally and compared with values obtained from molecular mechanics calculations (MM3). The close agreement of the results shows that the anomeric interactions, which are already integrated in the MM3 force field, are not dissimilar in the small‐ring cyclic and spirobicyclic ketals investigated in this study. The hybridization of the anomeric carbon atom apparently has no influence on the size of the anomeric effect detectable. The strain enthalpies of the cyclic and spirobicyclic ketals have therefore been calculated from their ΔHf°(g) values using the group increment scheme. Analysis and interpretation of all geminal interactions known in acetals/ketals is possible by means of a recently developed additivity scheme, and a single value of –38.6 kJ mol−1 has been obtained for the structural increment representing the inherent geminal O–C–O interactions.

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2,2-Dimethoxypropane

Slade¹

2001

Encyclopedia of Reagents for Organic Synthesis

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Preparation of Ketals from 2,2-Dimethoxypropane¹

Cited by 61 publications

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The Microstructure of Poly(divinyl acetal)s as Determined by 13C NMR Spectroscopy. Ring Stereochemistry and Isomerization Propagation

The Microstructure of Poly(divinyl acetal)s as Determined by 13C NMR Spectroscopy. Ring Stereochemistry and Isomerization Propagation

Does the Anomeric Effect in Ketals Depend on the Hybridization of the Central Carbon Atom?

2,2-Dimethoxypropane

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Preparation of Ketals from 2,2-Dimethoxypropane1

Cited by 61 publications

References 0 publications

The Microstructure of Poly(divinyl acetal)s as Determined by 13C NMR Spectroscopy. Ring Stereochemistry and Isomerization Propagation

The Microstructure of Poly(divinyl acetal)s as Determined by 13C NMR Spectroscopy. Ring Stereochemistry and Isomerization Propagation

Does the Anomeric Effect in Ketals Depend on the Hybridization of the Central Carbon Atom?

2,2-Dimethoxypropane

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Preparation of Ketals from 2,2-Dimethoxypropane¹