Cyclodecane-diones

Problem 23.9 What product would you expect to obtain from base treatment of 1,6-cyclodecane-dione ... 

When cyclodecane-1,6-dione is treated with sodium carbonate, the product gives a UV spectrum similar to that of 1 -acetyl-2-methylcyclopentene. Propose a structure for the product, and give a mechanism for its formation. 

In summary, intramolecular reactions of a considerable variety of diones provide interesting mechanistic questions as well as a route forj construction of four- and five-membered rings in high photochemical and chemical yields. Except for a synthesis of cis- and trans-bicyclo[7.1.0]decan-2-one from cyclodecane-1,2-dione 122), this potential has been ignored. 

Cyclodecan 2-Diazo-l-oxo- X/4, 562f. (aus Hydrazon) E14b, 1167 (Dion - R — S02 - N3) Cyclohexen 3-Hydroximino-2-pyrrolidino- E14b, 301 (CH2 - ... 

DIBAL-H/n-butyllithium, in cyclic and acyclic systems with iron pentacarbonyl, in cyclodecanes with lithium dihydrodimethoxyaluminate(III)/copper(I) iodide, and in cyclohexane and cyclopentane systems with NaH/sodium r-butylpentyl/Ni(OAc)2. ° The monoreduction of 1,3-diketones can be carried out under similar conditions, as illustrated by the reaction of a substituted cyclohexane-1,3-dione with oxalyl chloride to give the corresponding 1-chlorocyclohexenone, which was subsequently reduced to the enone with zinc-silver couple (Scheme 45). Kropp et al. have reported the photolytic reduction of vinyl iodides in acyclic systems however, when an a-hydrogen is present, formation of the diene product is a limiting side reaction (Scheme 46). For a more extensive discussion of vinyl halide reductions, see the preceding chapter in this volume. 

Cyclodecane-l,6-dione has been found to have a dipole moment of 0.7 A short review of the determination of conformations of the germacrene type of sesquiterpenes using nuclear Overhauser effects and the influence of these conformations on Cope rearrangements in these systems, has been published. 

Cycloalkane-1,2-diones dimerize on treatment with base thus cyclodecane-, cyclododecane-, and cyclotetradecane-1,2-diones were converted into (222 n = 7 1% n = 9 or 11, 40%). The major product from cyclodecane-l,2-dione was the conjugated monodehydration product. This could not, however, be dehydrated... 

Dicarbonyl Compoonds.—Wittig reactions of cycloheptatriene-1,6-dialdehyde to form bridged hetero[ll]annulenes are discussed. The kinetics of formation of the cyclic adduct between cyclodecane-1,2-dione and trimethyl phosphite have been discussed. ... 

Two other symmetric cycHc diones show unique behavior. Cyclodecane-1,6-dione is photoinert, both as a solid and in solution. Evidence indicates that it undergoes excited-state y-hydrogen abstraction, but the biradical does nothing except revert to ground-state reactant, presumably for the same reasons as the 1,4-biradical from cyclodecanone. Unlike the monoketone, the dione has no e-hydrogens to abstract. 

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