Transannular Cyclization with Grignard Reagents: Facile Synthetic Routes to Oxaadamantane and Protoadamantane Derivatives

Abstract

A simple and efficient synthetic route to different adamantanoid derivatives such as disubstituted oxaadamantane derivatives, trisubstituted protoadamantane, and trisubstituted adamantane derivatives starting from same precursor, 7-exo-epoxymethylene[3.3.1]nonan-3-one, is described.

Synthesis of 1,2-Disubstituted Adamantane Derivatives by Construction of the Adamantane Framework

“…The cyclization of starting material 168 was first demonstrated using potassium tert-butoxide as a base [54]. The prepared racemic diol 171a was rearranged with perchloric acid in hot aqueous dioxane to afford the racemic 1,3,4-trisubstituted adamantane diol 173 in 80% [92]. A study to probe the difference in reactivity of zwitterionic m-quinone methides, generated by photo-induced excited-state proton transfer (ESPT), and carbocations generated thermally in acidic media was carried out (Scheme 44).…”

“…The cyclization of starting material 168 was first demonstrated using potassium tert-butoxide as a base [54]. The prepared racemic diol 171a was rearranged with perchloric acid in hot aqueous dioxane to afford the racemic 1,3,4-trisubstituted adamantane diol 173 in 80% [92]. Epoxy ketone derivative 168 of the ketoolefine 65 (Scheme 15) was reacted with Grignard reagent to produce the 4-alkyl-4-hydroxyprotoadamantan-1-ols 171ab in high yields (Scheme 43).…”

Novel 2,4-Methanoadamantane-Benzazepine by Domino Photochemistry of N-(1-adamantyl)phthalimide

“…In the context of the research in the Majerski group on the synthesis and chemistry of adamantane and strained adamantane derivatives, we became interested in adamantane phthalimides and the possibility of their photochemical transformation to biologically active compounds such as benzazepindiones. One of the pathways toward benzazepines is the photochemical homolytic H-activation or electron transfer initiated decarboxylative cyclization of phthalimides, which has been the subject of intensive research interest .…”