Zur Polymerisation cyclischer Kohlenwasserstoffe. VI. Die Stereochemie der Cyclopentadien‐polymerisation

Norbornane-exo-cis-2,3-dicarboxylic acid

“…The product was recrystallized from doubly distilled water, giving colourless crystalline (I) in 88% yield (0.58 g, 3 mmol). The melting point of 424±425 K agrees with 425±426 K reported by Alder & Stein (1933) and Bartlett & Schneider (1946), although Craig (1951) measured a melting point of 428±429 K for freshly prepared (I) and 431±432 K after several days. Single crystals of (I) suitable for X-ray study were grown from ethyl acetate.…”

2-Norbornene-exo-cis-5,6-dicarboxylic acid

“…It is noteworthy that the melting point of our crystals (from ethyl acetate) is close to those found by Alder & Stein (1933) and Bartlett & Schneider (1946) for the samples crystallized from water (421±422 K). However, Craig (1951) reported that, under such conditions, only a monohydrate of (I) (m.p.…”

“…Various stereoisomers of 5,6-dicarboxylic acids with a 2-norbornene or 7-oxanorbornene core, and their norbornane analogues, are easily accessible through the Diels±Alder reaction (Diels & Alder, 1928;Alder & Stein, 1933). The crystal structure of 2-norbornene-(or bicyclo[2.2.1]hept-2ene-)-endo-cis-5,6-dicarboxylic acid has been determined repeatedly by Avitabile et al (1973), P¯uger et al (1973) and, at low temperature, by Bolte et al (2000).…”

“…2-Norbornene-exo-cis-5,6-dicarboxylic acid, or bicyclo[2.2.1]hept-2-ene-exo-cis-5,6-dicarboxylic acid, (I), was prepared by the usual route of hydrolysing the corresponding exo-anhydride, obtained in turn by`thermodynamic' Diels± Alder addition of cyclopentadiene to maleic anhydride at high (451 K) temperature (Diels & Alder, 1928;Alder & Stein, 1933).…”

Orientation of azide addition to homoconjugated dienes

“…Since the lowest field bridgehead hydrogen (6 3.10) should be H, of 13b, the signal at 6 2.98 is deduced to be due to H, of 13a. Addition of phenyl azide to endo-dicyclopentadiene has been reported several times (12,13) but no evidence as to the homogeneity of the product has been available. Indeed the rather sharp melting range of the product could be construed as evidence for formation of a single triazoline adduct (1 4).…”