Inorganic Chemistry, Vol.38, No.21, 4777-4783, 1999
Reactions of dimethyl sulfite with diorganotin oxides. One-pot synthesis of methoxydiorganotin methanesulfonates through the Arbuzov rearrangement, spectroscopic characterization of these compounds and their derivatives, and X-ray crystal structures of n-Bu2Sn(X)OS(O)(2)Me (X = acac, bzbz, OH)
One-pot reactions of diorganotin oxides, R2SnO, with dimethyl sulfite under reflux conditions (125-127 degrees C) proceed via the Arbuzov rearrangement at the sulfur center, yielding the corresponding methoxydiorganotin methanesulfonates, R2Sn(OMe)OS(O)(2)Me [R = n-Pr (1), n-Bu (2), i-Bu (3), c-Hx (4)], as white, hygroscopic solids. These compounds react with beta-diketones [acetylacetone (Hacac), benzoylacetone (Hbzac), and dibenzoylmethane (Hbzbz)] to afford mixed-ligand organotin derivatives, R2Sn(X)OS(O)(2)Me [X = acac, R = n-Pr (5), n-Bu (6); X bzac, R = n-Pr (7), n-Bu (8); X = bzbz, R = n-Pr (9), n-Bu (10), i-Bu (11)]. Selective hydrolysis of the Sn-OMe bond in 1-3 occurs, resulting in the isolation of (mu-hydroxo)diorganotin methanesulfonates, R2Sn(OH)OS(O)(2)Me [R = n-Pr (12), n-Bu (13), i-Bu (14)]. All the compounds are characterized by elemental analyses and IR, multinuclear (H-1, C-13, and Sn-119) NMR, and mass spectra. Unequivocal evidence of the presence of the methanesulfonate group is provided by the X-ray crystal structures of 6, 10, and 13. [For 6: trigonal space group R (3) over bar (No. 148), a = 28.664(1) a, c = 13.056(1)Angstrom, Z = 18. For 10: triclinic space group P (1) over bar (No. 2), a 13.056(3) Angstrom, b = 14.062(3) Angstrom, c = 16.282(3) Angstrom, Z = 4. For 13: triclinic space group P (1) over bar (No. 2), a = 9.089(2) Angstrom, b = 12.040(2) Angstrom, c = 13.894(2) Angstrom, Z = 2]. For 6 and 10, the solid-state structural analyses reveal dimeric structures with a bridging bidentate methanesulfonate group forming a centrosymmetric eight-membered ring. Compound 13 possesses a polymeric sheet structure with repeating 20-membered macrocycles (including two four-membered [Sn(OH)](2) rings) by virtue of the bridging bidentate methanesulfonate groups. A search for a possible pathway to give Arbuzov-rearranged products 1-4 leads us to speculate that there is an initial catalytic transformation of dimethyl sulfite to methyl methanesulfonate via intermediate compounds, Bu2Sn(OMe)(2) (A) and [Bu2SnOMe](2)O (B). A and B subsequently react with methyl methanesulfonate to give 1-4.