Über den oxydativen Abbau der Dehydroisofenchosäure

Synthesis and reactivity of small ring bicyclic compounds

“…Both had a mass spectral molecular weight of 154, indicating that they were isomeric with the bicyclic ester 15d. The one present in the larger amount showed an IR carbonyl stretching frequency of 1740 cm ^, and a band at 890 cm ^, characteristic of a terminal methylene.The nmr spectrum (I.I8 (6), s, perturbed; 4.83(2), d, further split by allylie coupling; 2.0 (2), AB of ABX; (4), s + X of ABX) also indicated the presence of a terminal methylene, and confirmed the structure as 1-carbomethoxy-2-methylene-5*5dimethylcyclobutane. The less abundant isomer showed a carbonyl frequency of 1720 cm ^ and a C=C band at I665 cm ^, indicating a conjugated ester.…”

“…In 1919, doubt was cast upon this structure assignment by N. J. Toivonen (2). He reported that the dehydration of 1hydroxy-2,2-dimethylcyclopentan-4-one-1-carboxylic acid yielded a product which was identical with the keto-acid assigned structure 2 by Perkin and Thorpe.…”

Synthesis and reactivity of small ring bicyclic compounds

“…In 1919, doubt was cast upon this structure assignment by N. J. Toivonen (2). He reported that the dehydration of 1hydroxy-2,2-dimethylcyclopentan-4-one-1-carboxylic acid yielded a product which was identical with the keto-acid The strangely ambivalent chemistry of these compounds led to a series of papers concerning their true structures (4, 5?…”