Diels-Alder reactions tetrabutylammonium fluoride

In model studies, Sulikowski et al. [83] investigated the reactivity of the Diels-Alder adduct 98 resulting from the reaction of bromonaphthoquinone 91 with the diene 97. Two major types of oxidation products, the epoxides 100 and 101, resulted from oxygenation in the presence of tetrabutylammonium fluoride... 

The cyclopropenes were distilled directly from the reaction mixture and were characterized by trapping as Diels-Alder adducts with 1,3-diphenylisobenzofuran (X = Br, 77%, mp 107-109"C X = Cl, 54%, mp 104-106 C). The same method was used to generate the unstable 7-chlorobicyclo[4.1.0]hept-l(7)-ene which was trapped in situ by 1,3-diphenylisobenzofuran. Reaction of the silanes 2 with tetrabutylammonium fluoride in tetrahydrofuran gave 1,2-dibromocyclopropene (3a) or 1-bromo-2-chlorocyclopropene (3b) ... 

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