Azabicyclo octane cationic

Cycloadditions and Rearrangements. The addition of 2-oxyallyl cations to furan provides a route to oxabicyclo[3,2,l]octanes complementary to the cycloaddition of cyclopropanones to furan. Careful experimental studies have led to yields of preparative importance both with furan and with cyclopentadiene. Following the route to azabicyclo-octanes, dipolar addition to the pyrylium betaine (99) affords oxa-analogues (Scheme 23). Also reported are the addition of fiiran to 1-cyanonaphthalene, the formation of various cycloadducts of tropone and tropolone (Scheme 24), and the phototransformations of (100) (Scheme 25) and (101) (Scheme 26). Thermal addition gives (102) from (103) and similarly other 8-oxabicyclo-octanes are prepared from acyclic precursors. ... 

The direct synthesis of the morphinan skeleton (107) from (105) involves the intramolecular ring opening by the enolate anion of the in situ generated aziridine cation (106) (Scheme 41) <88J0C2144>. Compound (108) was found to rearrange thermally to the thermodynamically favored azabicyclo-[3.3.1]octane (110) via the aziridinium ion (109) (Scheme 42) <93CC758>. 

Poly(l-azabicyclo[4.2.0]octane) (polyconidine) was synthesized with bromo-acetic acid using microwave irradiation (Karabulut et al., 2008). 1-Azabicyclo[4.2.0] octane contains unsubstituted four-membeied azetidine ring. It was synthesized with microwave-assisted methods and used in cationic ring-opening polymerization as a monomer. 

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