Conformational analysis of 1-oxaspiro [4.5] decanes

✍ Scribed by J.J. Uebel; E.L. Nickoloff; W.T. Cole; C.B. Grant

• Publisher: Elsevier Science
• Year: 1971
• Tongue: French
• Weight: 210 KB
• Volume: 12
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)96938-2

✦ Synopsis

Our interest in l,l-disubstituted cyclohexanes has been stimulated by the discovery of a dramatic breakdown of the additivity relationship for conformational free energies in l-methylcyclohexanol. 2,3 The conformational AGO for this material (ca -* 0.3 kcal/mole) is much smaller than would have been expected b.i'-0.6 (0.9) = 1.1 (0.8) kcal/mole) f rom a consideration of the conformational free energies of the HO [0.6(0.9)) 4 and CH3 (1.7) groups.5 Similar observations have been made in other l,l-disubstituted cyclohexanes.6 As a natural outgrowth of this work, we were interested in observing the effects produced by linking the substituents together in a second ring. The formation of such a ring would place restrictions on the orientations available to the substituents, and make a ring size effect study possible. A recent communication dealing with the conformational analysis of 1-oxaspiro[4.5]decanes7 now prompts us to report some startling observations with the same general series of compounds. 1,3-Dioxaspiro [4,51 decanes, L& and 2 have been prepared by standard techniques. They