Creation of Unique Structures Especially Designed to Serve as Models for Investigation

2 Creation of Unique Structures Especially Designed to Serve as Models for Investigation 

Throughout the history of organic chemistry, urgent theoretical problems have emerged which required the study of structures which, at the time, were considered to be esoteric. It was thus necessary to synthesize the required 

Isolated examples of isomeric organic compounds were known as early as the 1830s. This phenomenon turned to be a touchstone for the structural theory of organic chemistry formulated in the 1850s owing to the efforts of Kekule, Cooper, and Butlerov. It was Butlerov who not only advanced the consistent explanation of isomerism in terms of this theory but also predicted the existence of all theoretically possible isomers for a number of simple C4 and C5 derivatives (1864). Subsequent synthesis of these isomers served as a convincing proof of the validity of the structural theory. 

It should also be mentioned that the predictions based on the van t Hoff-LeBel theory of stereochemistry were tested and ultimately substantiated by a plethora of experimental evidence, as, for example the preparation of optically active derivatives of allenes like 72 and quaternary ammonium salts of the type 73. 

Questions as to whether or not compounds of highly strained molecular 

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