Triazolinediones addition reactions

Paquette s group has recently synthesized and evaluated chiral 4-sub-stituted triazolinediones in Diels-Alder cycloadditions.63 For example, endo-(-)-bomylamine has been converted to an azo dienophile, which has been used to resolve 1,2,3-trimethylcyclooctatetraene (Scheme 6-VII). In addition, triazolinediones derived from a-methylbenzylamine and dehydroabietylamine have been prepared and their reactions with achiral 1,3-dienes were investigated.636 Unfortunately, these dienophiles did not show good kinetic enantioselection, but they are useful for the type of resolution shown in Scheme 6-VII.630... 

It has also been known for many years that the ene reaction with compounds such as 4-substituted-l,2,4-triazoline-3,S-diones can be applied to dienic polymers, either to achieve chemical modification, or, with difiinctional compounds, crosslinking. Butler et alP have now undertaken a detailed study of the addition of triazolinediones (R = CH3, C H5) to a range of diene polymers and copolymers. 

The alkenylidenecyclopropanes (104) and (105) react thermally with the electron-deficient acetylenes (106) exclusively in a [2 + 2] fashion to yield a mixture of the methylenecyclobutenes (107) and (108)." The preference for [2 -I- 2] addition in this reaction is in marked contrast to the course of the reaction between alkylidenecyclo-propanes and either 4-phenyl-1,2,4-triazolinedione or chlorosulphonyl isocyanate, neither of which gives any [2 -I- 2] addition products. 

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