99605-57-9Relevant articles and documents
Reactions of molecules with two equivalent functional groups. 5. Anomalous reactivity of 1,10-cyclooctadecanedione. Crystal and molecular structures of cis,cis-1,10-Diphenyl-1,10-cyclooctadiene and the stereoisomers of 1,10-diphenyl-1,10-cyclooctadecanediol
Macomber, Roger S.,Constantinides, Ioannis,Bauer, Jeanette Krause,Smith, Gregory,Button, Angela,Lindstrom, David O.
, p. 727 - 734 (1996)
The reaction of the title diketone (3) with phenyl Grignard produces (with rate constant k1) the conjugate base (6-M) of 10-hydroxy-10-phenylcyclooctadecanone (6), which is subsequently converted (with rate constant k2) to the conjugate base of the title diol, as a mixture of the cis (7, 55%) and trans (8, 45%) isomers. The ratio k2/k1, 2.2 ± 0.4, indicates that the carbonyl group in 6-M is 4.4 times as reactive as each carbonyl in 3. Competition experiments further demonstrate that the relative rates (per carbonyl) for addition of phenylmagnesium bromide to 3, 10-methylenecyclooctadecanone (11), and cyclopentadecanone (12) are 1.0:0.60:1.92. Possible reasons for this order of reactivity are discussed. Diols 7 and 8 undergo facile double dehydration to form the title diene 13, which is predicted by molecular mechanics calculations to be the most stable of the four possible symmetrical diene isomers. The structures of 7, 8, and 13 were secured by single-crystal X-ray studies.
