Zirconium-mediated Synthesis and Crystal Structure of 3,6-Diiodo-4,5-dialkyl-phthalic Acid Dimethyl Ester

摘要

A novel series of para-diiodobenzene derivatives, 3,6-diiodo-4,5-dialkyl-phthalic acid dimethyl esters, were prepared via cycloaddition of two TMS-substituted alkynes and dimethyl acetylenedicarboxylate, which was mediated by zirconocene. After iodination, three new compounds of 3,6-diiodo-4,5-dimethyl(dipropyl, dibutyl)-phthalic acid dimethyl esters(3a, 3b, 3c) were synthesized in high region-selectivity and yields, and characterized by NMR. The crystal structures were determined by single-crystal X-ray diffraction. The crystal of 3a(C12H12I2O4, Mr = 474.02) belongs to the triclinic system, space group P1 with a = 7.6238(10), b = 9.4571(12), c = 10.8221(14) ?, α = 66.611(10), β = 88.511(12), γ = 77.604(11)°, V = 697.93(16) ?3, Z = 2, F(000) = 444, Dc = 2.256 mg/m3, μ = 4.509 mm-1, T = 133(2) K, S = 1.014, R = 0.0229 and w R = 0.0547 for 2644 observed reflections with I > 2σ(I); the crystal of 3b(C16H20I2O4, Mr = 530.12) is of triclinic system, space group P1 with a = 9.4122(19), b = 10.626(2), c = 11.353(2) ?, α = 97.90(3), β = 113.83(3), γ = 110.22(3)°, V = 922.6(3) ?3, Z = 2, F(000) = 508, Dc = 1.908 mg/m3, μ = 3.422 mm-1, T = 113(2) K, S = 1.115, R = 0.0428 and w R = 0.1072 for 3971 observed reflections with I > 2σ(I); the crystal of 3c(C18H24I2O4, Mr = 558.17) belongs to the monoclinic system, space group P21/c with a = 26.396(2), b = 8.7560(8), c = 25.7970(18) ?, β = 91.721(4)°, V = 5959.6(8) ?3, Z = 12, F(000) = 3240, Dc = 1.866 mg/m3, μ = 3.184 mm-1, T = 113(2) K, S = 1.154, R = 0.0424 and w R = 0.0766 for 13056 observed reflections with I > 2σ(I).