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-Bu(2)Sn(X)OS(O)(2)Me (X = acac, bzbz, OH).
One-pot reactions of diorganotin oxides, R(2)SnO, with dimethyl sulfite under reflux conditions (125-127 degrees C) proceed via the Arbuzov rearrangement at the sulfur center, yielding the corresponding methoxydiorganotin methanesulfonates, R(2)Sn(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, R(2)Sn(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 (&mgr;-hydroxo)diorganotin methanesulfonates, R(2)Sn(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 ((1)H, (13)C, and (119)Sn) 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&thremacr; (No. 148), a = 28.664(1) Å, c = 13.056(1)Å, Z = 18. For 10: triclinic space group P&onemacr; (No. 2), a = 13.056(3) Å, b = 14.062(3) Å, c = 16.282(3) Å, Z = 4. For 13: triclinic space group P&onemacr; (No. 2), a = 9.089(2) Å, b = 12.040(2) Å, c =13.894(2) Å, 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, Bu(2)Sn(OMe)(2) (A) and [Bu(2)SnOMe](2)O (B). A and B subsequently react with methyl methanesulfonate to give 1-4.
Narula
Suraj P.
SP
The Scripps Research Institute, BCC-159, 10555N Torrey Pines Road, La Jolla, California 92037.
Kaur
Sukhjeevan
S
Shankar
Ravi
R
Verma
Sushma
S
Venugopalan
Paloth
P
Sharma
Surinder K.
SK
Chadha
Raj K.
RK