Halocyclization of Unsaturated Alcohols and Carboxylic Acids Using Bis(sym-collidine)iodine(I) Perchlorate

Synthesis of dioxane-based antiviral agents and evaluation of their biological activities as inhibitors of Sindbis virus replication

“…Intermediate (S)-4 was converted to 2-iodomethyl- [1,4]dioxane 19 13, 14 with imidazole, triphenylphophine, and iodine in a mixed solvent of toluene and tetrahydrofuran at ambient temperature in 84% yield. 15 Displacement of iodide from intermediate 19 13,14 with the lithiated anion derived from 1,3-dithiane afforded the product 20, which was readily hydrolyzed to yield aldehyde 21 with excess of methyl iodide and sodium bicarbonate in acetonitrile and water at 40 °C.…”

A Centennial Methodology for the Preparation of Heterocyclic Compounds: The Intramolecular Coiodination of Alkenes with Internal Oxygenated Nucleophiles

“…On the other hand, the preparation of β-lactones is very interesting and depends on reaction conditions. In contrast with butenoic acid that produces only β-lactones [28,61], the intramolecular coiodination of α ,αdimethylbutenoic acid, in small reaction time, produces βlactones, and, in longer reaction time, γ-lactones exclusively [62]. In fact, the propionolactone rearranges under the reaction conditions into the thermodinamically more stable butyrolactone.…”

“…However, curiously, oxirane preparation by intramolecular coiodination of allylic alcohols is rare [28,30], while several examples of the reaction applied to homoallylic alcohols to produce oxetanes are described in the literature [28,[32][33][34] The intramolecular coiodination of homoallylic alcohols can produce oxetanes or tetrahydrofurans through a 4-exo or a 5-endo pathways, respectively. In several studies, it was demonstrated that the nature of the formed ring can be controlled by the substitution pattern on the substrate, the formation of the five-membered ring being the typical reaction.…”

“…In several studies, it was demonstrated that the nature of the formed ring can be controlled by the substitution pattern on the substrate, the formation of the five-membered ring being the typical reaction. In contrast with homoallylic alcohol that produces 2-iodomethyloxetane along with 3-iodotetrahydrofuran [28], the coiodination of α,α-disubstituted or γ-substituted homoallylic alcohols produces exclusively the corresponding oxetanes through a 4-exo cyclization (Scheme 6).…”

Cyclization of Homoallylic Alcohols with Iodine/Iodine(III)

“…1 The iodocyclization of homoallylic alcohols with terminal double bonds leads to the formation of oxetanes. 2 This happens because the 5-endo-trig cyclization is not favored for this type of substrate. An alternative protocol was developed by our group.…”