Oxidations by the system “hydrogen peroxide - manganese(IV) complex - acetic acid” — Part II. Hydroperoxidation and hydroxylation of alkanes in acetonitrile

摘要: Abstract Higher alkanes (cyclohexane, n -pentane, -heptane, methylbutane, 2- and 3-methylpentanes, 3-methylhexane, cis - trans -decalins) are oxidized at 20 °C by H 2 O in air acetonitrile (or nitromethane) solution the presence of manganese(IV) salt [L Mn 3 ](PF 6 ) (L = 1,4,7-trimethyl-1,4-7-triazacyclononane) as catalyst. An obligatory component reaction mixture is acetic acid. Turnover numbers attain 3300 after h, yield oxygenated products 46% based on alkane. The oxidation affords initially corresponding alkyl hydroperoxide predominant product, however later these compounds decompose to produce ketones alcohols. Regio- bond selectivities high: C(1) : C(2) C(3) C(4) ≈ 1 40 35 1° 2° 3° (15–40) (180–300). with both isomers decalin gives (after treatment PPh alcohols hydroxylated tertiary positions cis/trans ratio ∼ case -decalin, 30 -decalin (i.e. latter stereospecific). Light (methane, ethane, propane, normal butane isobutane) can be also easily same reagent solution, conditions being very mild: low pressure (1–7 bar alkane) temperature (−22 +27 °C). Catalyst turnover 3100, 22% yields oxygenates higher temperatures. formed (hydroperoxide: ketone: alcohol) depends strongly especially catalyst concentration (at ketone predominantly produced).