Zur Kenntnis der Diensynthese mit unsymmetrischen Addenden Die Diensynthese des trans‐1‐Phenyl‐butadiens mit Acrylsäure und mit Acrolein

Stereochemistry of the Diels-Alder Reaction.

“…Alder has reported that several cis 1-substituted dienes, on being heated to high temperatures with maleic anhydride, give adducts of the trans diene (35,36). Epimerization may also occur during workup of the products: the l-phenyl-l,3-butadiene-acrolein adduct isomerizes from cis to trans during purification with sodium bisulfite (54), and alkaline hydrolysis of the cis adduct of cyclopentadiene and dimethyl maleate gives the trans diacid (103).…”

“…One difficulty previously mentioned is that the all-cis adducts are prone to isomerize to their more stable trans isomers under vigorous conditions. Some original reports of trans adducts from acyclic dienes have been corrected in recent years by showing that, at low temperatures and in the absence of equilibrating catalysts, the cis isomer predominates (54,55,207,208). Exceptions to the rule that cis adducts are formed are the írons-2-phenylcyclohexenecarboxylic acid derivatives resulting from the addition of ¿rons-1-phenyl-1,3-butadiene to acrylonitrile and acrylamide (207), and of methyl 1-phenyl-1,3-butadiene-2-carboxylate to acrylic acid (20).…”

The Synthesis of Derivatives of 1-Indanone and Indenone

“…1 The product was recrystallized from hexane at -5-0°two times. 5 These are purified yields. h p-Toluenesulfonic acid.…”

Nuclear Structure of the Water-soluble Polycarboxylic Acids from the Oxidation of Bituminous Coal: The Hydrogenolysis Reaction1

“…Compounds I and II have been synthesized by Gutsche9 and Alder and co-workers. 10 Although the latter investigators encountered difficulty in the cis -* trans isomerization of methyl 2-phenylcyclohexylcarboxylate and reported no yield for this step, we have found that the trans ester may be obtained readily in 96% yield. This modified route would appear to be more practical than that employed by Gutsche.9 We have now established that 2-phenylcyclohexylamine prepared by the reduction of 2-phenylcyclohexanone oxime with sodium and alcohol,11 or via the Diels-Alder reaction of -nitrostyrene and butadiene12 has the trans configuration.…”