Réduction de (+)-3-[di(alkylsulfanyl)méthylène]bornan-2-ones. Formation de complexes zinciques chiraux. Structure cristalline et dichroïsme circulaire

Abstract

Abstract According to the structure of the reacting compound, two different splits occur, when reduction of a 3-[di(alkylsulfanyl)methylene] camphor is performed with zinc and acetic acid, giving either 3-(monoalkylsulfanylmethylene)-2-bornanones or tetrahedral zinc complexes of an intermediary 3-(thioalkylsulfanylmethylene)-2-bornanone. Circular dichroism shows exciton interaction between the two conjugated systems. Molecular structure of one of these complexes was carried out by single crystal X-ray diffraction methods. Crystals of C36H42O2S4Zn belong to space group P1 with a = 10.312(1) Å, b = 11.308(2) Å and c = 16.286(2) Å, α = 91.128(10)°, β = 106.553(11)°, γ = 106.247(10)°, Z = 2, T = 293 K. The final R is 0.082 for 5048 unique reflections. The cohesion of the crystal is the result of van der Waals interactions.