28047-93-0Relevant academic research and scientific papers
Oxymetallation. Part 16. Modified Procedures for Reducing Peroxymercurials: Conversion of Non-terminal Alkenes into Secondary Alkyl t-Butyl Peroxides
Bloodworth, A. J.,Courtneidge, J. L.
, p. 1797 - 1806 (2007/10/02)
Various procedures for reducing PhCH(OOBut)CH2HgO2CCF3 or PhCMe(OOBut) have been investigated in an attempt to optimize yields of the mercury-free peroxides.Effects of varying the concentration of borohydride and the mode of mixing, and of including a phase transfer catalyst, have been assessed for the two phase system of alkaline NaBH4 and dichloromethane and reductions have been carried out in a single phase by using Bu4NBH4 in dichloromethane.The t-butyl peroxymercurials t)CH(HgX)R> derived from cis- and trans-but-2-ene, cis- and trans-hex-3-ene, cyclopentene, cyclohexene, and norbornene have been reduced under the optimum conditions of slowly adding base-pretreated peroxymercurials in dichloromethane to a large excess of alkaline NaBH4.Product analyses support the idea that the reactions proceed via β-peroxyalkyl radicals t)CHR>, but show that, except for the norbornyl derivative, epoxides are the dominant products; cyclopentyl, cyclohexyl, and exo-norbornyl t-butyl peroxides have been isolated in yields of 2, 13, and 37 percent, respectively.Better, but still modest, yields (24-36 percent) have been obtained for butan-2-yl, hexan-3-yl, and cyclopentyl t-butyl peroxides by silver trifluoroacetate-assisted t-butyl perhydrolysis of the alkyl bromides, but competing dehydrobromination lowered the yield (6 percent) of the cyclohexyl compound.Vastly improved yields (ca. 60 percent) of butan-2-yl, cyclopentyl, and cyclohexyl t-butyl peroxides have been achieved by reduction of the corresponding peroxymercurials with neat Bu3SnH.
