Bicyclic Amide Acetals. Synthesis and Reactions

Chemoselective isomerization of amide-substituted oxetanes with Lewis acid to give oxazine derivatives or bicyclic amide acetals

“…¶ Analogous amide acetals of the bicyclo[n.3.0] type (n = 3 or 4) have already been synthesized by intermolecular cycloaddition or transacetalization, and they have been reported to possess high susceptibility to nucleophiles. 6 Similarly compounds 7 were so sensitive to moisture that hydrolytic fission proceeded rapidly under normal conditions.∑ When the above isomerization was run for 24 h at 100 °C and above, most of the 7 produced was consumed. The final products were oligomers having a polyether backbone.…”

Dioxazocinium Ortho Esters: A Class of Highly pH‐Vulnerable Amphiphiles

“…Lipid synthesis: Exposure of ammonium salt 5 6 (Scheme ) to NaOMe gives rise to methyl ortho ester 6 and to ketene acetal 7 as the consequence of a competing Hofmann‐type elimination 7. We reasoned that the ketene acetal moiety in 7 could serve as a progenitor of amphiphilic ortho esters.…”

Synthesis of Iminium Salts, Orthoesters and Related Compounds

“…7,9,143,156 DMF was converted to the corresponding iminium salt (27) by the following reagents: 5 perfluorobutyryl chloride, 2,2-dichlorobenzodioxole (36) and 2,2,2-trichlorobenzodioxaphosphole (37). (36) (37) (i) Hydrogen halides to nitriles or imidoyl halides…”