Synthetic studies on tricyclospirodienones; model chemistry for novel mimics of steroid substrates

Diels–Alder routes to angularly halogenated cis-fused bicyclic ketones: readily accessible cyclynone intermediates

“…Interestingly, under thermal conditions, the Rawal diene ( 4 )7 and bromocyclohexenone 1a undergo cycloaddition followed by spontaneous elimination of the dimethylamine and hydrogen bromide moieties, to cleanly deliver the aromatic bicyclic adduct 5a 8 as a single regioisomer in 72% yield. The bromocyclopentenone 1d undergoes an analogous sequence to provide compound 5b .…”

N-Phenylselenophthalimide

“…37 An example is shown in eq 25. 37a NPSP was also effective in promoting the intramolecular alkylation of a phenol to the corresponding 4-substituted dienone (eq 26), 38 presumably via an initially formed seleniranium ion intermediate. α α α-Selenenylation of Carbonyl Compounds.…”