Free radical addition of carbon tetrahalides to the 3,7-dimethylenebicyclo [3.31] nonane

Experimental and theoretical studies on the transannular cyclizations of 3,7-dimethylenebicyclo[3.3.1]nonane with polyfluoroalkyl radicals

“…Hence, because the MIN3 is separated from MIN2 by relatively high barrier, formation of adamantane derivatives in the reaction of 1 with radical is possible in low-homolyzable solvents, where the lifetime of MIN2 is relatively high. This agrees nicely with the experimental data, where the ratio of noradamantane versus adamantane derivative is larger (9:1) in CBr 4 than in less homolizabylity CCl 4 (3:1) [21]. Radical additions studied herein experimentally in presence of R F I, which serves as an effective radical trap for MIN2, lead to noradamantane derivatives exclusively.…”

“…The exclusive formation of noradamantane derivatives differs from the previously observed selectivities for the radical cyclization of 3,7-dimethylenebicyclo[3.3.1]nonane [21][22][23][24]. For instance, in the reaction of 1 with CCl 4 the 3:1 ratio of the respective noradamantane/adamantane products was found; the reaction with CBr 4 is more selective (9:1) [21].…”

“…Adamantyl and noradamantyl moieties are often used as the building blocks for new drugs with antiarrhythmic, hypoglycemic, antiviral and other types of physiological activity [11][12][13][14][15]. Convenient and selective preparations of functional derivatives of adamantane and noradamantane are based on transannular cyclizations of bicyclo[3.3.1]nonane dienes with electrophilic or radical agents [16][17][18][19][20][21][22][23][24]. It has been shown previously, that transannular cyclizations of polyunsaturated bicyclo[3.3.1]nonane derivatives with electrophiles (iodine, bromine, acids, NHlgS (Hlg = Cl, Br, I), 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate)) [16][17][18][19][20] lead to adamantane derivatives.…”

“…It has been shown previously, that transannular cyclizations of polyunsaturated bicyclo[3.3.1]nonane derivatives with electrophiles (iodine, bromine, acids, NHlgS (Hlg = Cl, Br, I), 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate)) [16][17][18][19][20] lead to adamantane derivatives. In contrast, noradamantane, and adamantane derivatives, are formed in the reactions with radical agents (CCl 4 /AIBN, CHCl 3 /g-irradiation, C 6 H 5 SH, CH 3 PhSO 2 Hlg (Hlg = Cl, Br)) [21][22][23][24]. The ratio of adamantane/noradamantane products depends on the reagent used [21], and this fact still awaits its mechanistic interpretation.…”

“…In contrast, noradamantane, and adamantane derivatives, are formed in the reactions with radical agents (CCl 4 /AIBN, CHCl 3 /g-irradiation, C 6 H 5 SH, CH 3 PhSO 2 Hlg (Hlg = Cl, Br)) [21][22][23][24]. The ratio of adamantane/noradamantane products depends on the reagent used [21], and this fact still awaits its mechanistic interpretation.…”