Acid-Catalysed Dimerization of exo-2-Arylbicyclo[2,2,1]heptan-endo-2-ols

Abstract

This paper discusses the reactions of exo-2-arylbicyclo[2,2,1]heptan-endo-2-ols with concentrated perchloric acid which afford the dimers (1RS,2SR,4SR,2'RS,4'SR,7'SR,8'RS)-7'-(aryl)spiro[bicyclo-[2,2,l]heptane-2,9'-tetracyclo[8,4,0,0^2,7,0^4,8]tetradeca-10',12,14'-triene] and (1RS,2SR,4SR,1'SR,- 2'RS,10'RS,11'RS)-2-(aryl)spiro[bicyclo[2,2,1]heptane-2,9' tetracyclo[9,2,1,0^2,10,0^3,8]tetradeca- 3'5',7'-triene]. The crystal structure of (1RS,2SR,4SA,1'SR,2'RS,10'RS,11'RS)-5'-chloro-2'-(4~'-chlorophenyl)spiro[bicyclo[2,2,1]heptane-2,9'-tetracyclo[9,2,1,0^2,10,0^3,8]tetradeca-3',5',7'-triene], determined from X-ray diffraction data and refined by least-squares to a residual of R 0.137 (3715 observed reflections), is reported. The crystals are monoclinic, P2₁/c, with two molecules in the asymmetric unit; a 10.062(1), b 19.004(2), c 21.539(2)Å β 96.42(1)º, Z 8.