115377-06-5Relevant academic research and scientific papers
Iodomethylene lactone formation. An improved synthesis
Mawson,Routledge,Weavers
, p. 4665 - 4678 (1995)
Detailed examination of the free radical induced cyclisation of the propiolate ester of trans-2-iodocyclopentanol has revealed a rather inefficient radical chain. The optimum conditions found used dibenzoyl peroxide as initiator and benzene as the reaction solvent. High concentrations of initiator were required and significant quantities of iodobenzene were formed. Portionwise addition of initiator was found to be beneficial, but use of inert atmospheres gave no advantage. Although the reaction was quite highly selective to give predominantly the (E)-iodomethylene lactone, trace quantities of the (Z)-isomer were isolated. Other minor by-products could be attributed to trapping of the intermediate vinyl radical by the solvent. An alternative, improved route to iodomethylene lactones via fluoride ion desilylation of the trimethylsilyl substituted derivatives has been developed.
Photoisomerisation of (E)-Iodoalkylidene Lactones. A Route to (Z)-Iodoalkylidene Lactones
Haaima, Gerald,Hanton, Lyall R.,Lynch, Mary-Jeanne,Mawson, Simon D.,Routledge, Anne,Weavers, Rex T.
, p. 2161 - 2174 (2007/10/02)
Photochemically induced free-radical cyclisation of iodo acetylenic esters provides low yields of mixtures from which both (E)- and (Z)-iodoalkylidene lactones may be isolated.However, photoisomerisation of (E)-iodoalkylidene lactones, which have previously been obtained in good yields by dibenzoyl peroxide induced cyclisation of iodo acetylenic esters, provides (E)/(Z)-mixtures from which the previously inaccessible (Z)-isomers may be isolated by chromatography.Also reported is a collection of IR, UV and NMR spectral data, all of which provide useful information relating to the stereochemistry of the iodoalkylidene lactones.A comparison of the cryctal structures of the (E)- and (Z)-isomers of a trimehylsilyl iodomethylene lactone is also included.
ALKYLIDENE LACTONE SYNTHESIS
Haaima, Gerald,Lynch, Mary-Jeanne,Routledge, Anne,Weavers, Rex T.
, p. 5203 - 5214 (2007/10/02)
The iodoalkylidene lactones formed by reaction of alkenes with acetylenic acids in the presence of N-iodosuccinimide and subsequent free radical cyclisation, can be de-iodinated photochemically or alkylated with lithium diorganocuprate reagents to yield a variety of α-alkylidene lactones.
IODOVINYLIDENE LACTONE SYNTHESIS. FREE RADICAL CYCLISATION OF IODO ACETYLENIC ESTERS.
Haaima, Gerald,Weavers, Rex T.
, p. 1085 - 1088 (2007/10/02)
Propiolic acids add to alkenes in the presence of N-iodosuccinimide to give iodo acetylenic esters.These, on treatment with dibenzoyl peroxide, undergo cyclisation to yield (E)-iodovinylidene butyrolactones.Subsequent alkylation with lithium dimethylcuprate occurs by replacement of the iodine.
