PART I. SYNTHESIS AND CHARACTERIZATION OF 3,3-DIMETHYL-3-STANNABICYCLO(3.2.1)OCTANE AND ITS ANALOGUES. PART II. THE AQUEOUS HYDROLYSES OF METHOXY SUBSTITUTED PHOSPHONIUM SALTS (ORGANOTIN COMPOUNDS)
Part I. The synthesis and characterization of twelve compounds in the 3-stannabicyclo 3.2.1 octane and -oct-6-ene series are described. 3,3-Dimethyl-3-stannabicyclo 3.2.1 octane (2) was successfully synthesized in 50% yield. It was converted to the monochloro derivative (5b) by reaction with mercuric chloride. Other derivatives of 3-stannabicyclo 3.2.1 octane were synthesized by the reaction of 5b with an appropriate reagent. Most of these reactions were clean, and afforded a good yield of the desired product. Moreover, no ring cleavage of 5b was observed. The structures of these compounds were supported through two or more of the following methods: C,H-analysis, IR, ('1)H NMR, ('13)C NMR, ('119)Sn NMR, and mass spectra. The results were consistent with known organotin compounds as well as their silicon counterparts. Tentative endo/exo stereochemical assignments of some of these compounds were made from the ('1)H NMR chemical shift of the Sn-CH(,3) group. Part II. Each phosphonium salt: exo-3-methoxy-endo-3-phenyl-3-phosphoniabicyclo 3.2.1 oct-6-ene tetrafluoroborate (14) and its isomer (15), and trans-1-methoxy-4-tert-butyl-1-phenylphosphorinanium hexafluorophosphate (16) and its isomer (17), was hydrolyzed with varying amounts of water in acetonitrile solution to afford the corresponding phosphine oxides; the results ranged from nearly complete retention to predominant inversion. It appeared from oxygen-18 labeling experiments that aqueous hydrolyses of 14 and 17 occurred via exclusive P-O bond cleavage whereas the hydrolyses of 15 and 16 occurred via P-O and C-O bond cleavage. A kinetic study of homogeneous hydrolysis of each salt 14-17 was carried out in acetonitrile solution (constant temperature) and the resultant pseudo-first-order reaction was followed by ('1)H NMR spectroscopy. The rate constant of hydrolysis and the stereochemical outcome were affected by the concentration of water, the acidity of the solution, and the geometry of the salts. Attempts to control the pH of the solution during the hydrolyses of 14 and 17 by the following methods were only partially successful: (1) addition of an equivalent of an organic base to neutralize the HBF(,4) or HPF(,6) generated during the hydrolysis, (2) performing the hydrolysis in a buffer solution, or (3) addition of excess HBF(,4) to keep the pH of the solution constant. Mechanisms for homogeneous aqueous hydrolysis of 14-17 were proposed. (Abstract shortened with permission of author.)
"PART I. SYNTHESIS AND CHARACTERIZATION OF 3,3-DIMETHYL-3-STANNABICYCLO(3.2.1)OCTANE AND ITS ANALOGUES. PART II. THE AQUEOUS HYDROLYSES OF METHOXY SUBSTITUTED PHOSPHONIUM SALTS (ORGANOTIN COMPOUNDS)"
(January 1, 1985).
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