Adducts of Tricyclo[4.1.0.02,7]heptane hydrocarbons with methane- and Halomethanesulfonyl Thiocyanates and their transformations in the presence of bases (nucleophiles)

Abstract

1-R-Tricyclo[4.1.0.0 2,7 ]heptanes (R = H, Me, Ph) take up methane-and halomethanesulfonyl thiocyanates XCH 2 SO 2 SCN (X = H, Cl, Br) at the central C 1 -C 7 bond in benzene at 20°C with high anti-selectivity to give bicyclo[3.1.1]heptane derivatives with the 7-endo-oriented sulfonyl group and the thiocyanato group in the geminal position with respect to the R substituent. The syn-adducts lose HSCN molecule by the action of potassium tert-butoxide in THF at 0°C or on heating in boiling aqueous dioxane containing NaOH with formation of 1-(X-methylsulfonyl)tricyclo[4.1.0.0 2,7 ]heptanes. Under analogous conditions the anti-adducts (X = Me) are converted into 1,2-bis(7-syn-methylsulfonyl-6-endo-R-bicyclo[3.1.1]hept-6-exo-yl)disulfanes. The anti-adduct derived from unsubstituted tricyclo[4.1.0.0 2,7 ]heptane and MeSO 2 SCN reacted with methyllithium or phenylmagnesium bromide to produce 7-anti-methyl(phenyl)sulfanyl-6-endo-methylsulfonylbicyclo-[3.1.1]heptanes which were also obtained by photochemical addition of MeSO 2 SMe(or Ph) to tricyclo-[4.1.0.0 2,7 ]heptane. Geometric parameters of radical intermediates in the sulfonylation of 1-R-tricyclo-[4.1.0.0 2,7 ]heptanes were optimized ab initio using 6-31G basis set.We previously reported [1-6] on the addition of arene-and methanesulfonyl halides at the central bicyclobutane bond in tricyclo[4.1.0.0 2,7 ]heptanes I-III. In keeping with the proposed radical mechanism, the addition is initiated by strict endo attack by sulfonyl radical on the unsubstituted position at the C 1 −C 7 bond to produce a mixture of syn-and anti-adducts having norpinane structure, the anti-adduct prevailing. We also showed [7] that sulfur-containing derivatives of a r e n e s u l f o n i c a c i d s , s u c h a s A r S O 2 S P h a n d ArSO 2 SCN, react with tricycloheptane I in a similar way with moderate anti-stereoselectivity. In continuation of our studies on regio-and stereoselectivity of radical sulfonylation of tricycloheptane derivatives, in the present work we examined reactions of compounds I-III with methane-, chloromethane-, and bromomethanesulfonyl thiocyanates. The expected products, i.e., norpinane derivatives having sulfonyl and thiocyanato groups, attract interest as subjects for subsequent transformations in reactions with bases (nucleophiles), and some results of such transformations are reported here. The radical addition of methanesulfonyl thiocyanate at multiple carbon-carbon bonds was described in [8], whereas there are no published data on analogous reactions with chloro-and bromomethanesulfonyl thiocyanates.The initial sulfonyl thiocyanates were synthesized from methane-and halomethanesulfonyl halides which were reduced to the corresponding methanesulfinates with Na 2 SO 3 in the presence of NaHCO 3 in aqueous medium at 20°C. Methanesulfinates thus obtained were converted into sulfonyl thiocyanates by treatment of their aqueous solutions with a solution of dirhodan in benzene according to the procedure described in [9]. As a result, we obtained a solution of the corres...

Unusual transformation of the 1-bromotricyclo[4.1.0.02,7]-heptane adduct with methanesulfonyl thiocyanate in the presence of DBU

“…Therefore, we presumed [1] that the reaction begins with 1,3-elimination of hydrogen bromide and restoration of the tricyclo[4.1.0.0 2,7 ]heptane system, which then undergoes opening with transition of the sulfonyl group to the exo position. solvent) thiolate ion B is oxidized to disulfane 6 with atmospheric oxygen or cyanogen bromide [2]. In the reaction carried out in methylene chloride, disulfane 6 is formed as a minor product (Scheme 2).…”