24618-32-4Relevant academic research and scientific papers
Oxymetallation. Part 15. Oxidation of Hex-1-ene by Thallium(III) Trifluoroacetate in Methanol
Bloodworth, A. J.,Lapham, David J.
, p. 3265 - 3271 (2007/10/02)
Hex-1-ene reacts with thallium(III) acetate in methanol to afford 2-methoxyhexylthallium diacetate which undergoes no appreciable decomposition when kept in methanol at room temperature for one week, but which, upon treatment with solid potassium bromide and a catalytic amount of 2,6-dimethyl-18-crown-6, cleanly affords a high yield of 1-bromo-2-methoxyhexane (1).By contrast, the methoxythalliation adduct obtained with thallium(III) trifluoroacetate undergoes oxidative dethalliation fairly rapidly (ca. 85percent dethalliation after 2 h) to give 1,2-dimethoxyethane (2) and 2-methoxyhexanol (3) as major products.It is suggested that compounds (2) and (3) arise by facile ligand exchange followed by transfer of methoxy- or hydroxy-groups from thallium to C-1 in an SNi process.If the methoxythalliation is carried out with thallium(III) trifluoroacetate in dichloromethane with methanol (2 equiv.) the oxidative dethalliation is complete after only 1 h, but 1-methoxyhexan-2-ol (4) and 2-methoxy-1-trifluoroacetoxyhexane (5) are obtained as additional products.It is suggested that ligand exchange is not effective under these conditions and that dethalliation via an oxonium ion, which leads to compounds (2) - (4), competes with the SNi process which affords compounds (5).Only small amounts (10percent) of hexan-2-one are obtained in the oxidations.
