Efficient synthesis of substituted benzenes from 1,3-dienes or 1,4-cyclohexadienes with KMnO4 under mild conditions

Continuous catalyst-free aromatization of γ-terpinene using air as an oxidant

“…Terpenes are a widely available, sustainable source of building blocks for the chemical industry. Terpenes are obtained by fractional distillation of turpentine 1 and can be modified by catalytic methods 2 such as hydrogenation, [3][4][5] dehydrogenation, [6][7][8][9][10][11][12][13][14] rearrangement, [15][16][17] and oxidation reactions. 18,19 p-Cymene is produced industrially via Friedel-Crafts alkylation of toluene with propene.…”

Alumina supported potassium permanganate: an efficient reagent for chemoselective dehydrogenation of 2-imidazolines under mild conditions

“…13 One of the most striking examples of a change in chemical reactivity and selectivity that has been reported to date is with the well-known oxidant potassium permanganate. 14 Previously, alumina supported potassium permanganate has been used for the oxidative cleavage of enamine double bonds, 15 dehydrogenation of 1,4-cyclohexadienes to aromatics, 16 oxidative cleavage of oximes, 17 oxidation of thiols and sulfides, 18 oxidative deprotection of TMS and THP ethers, ethylene acetals and ketals, 19 oxidation of alcohols, 20 oxidation of urazoles, 21 oxidation of a-hydroxysilanes, 22 oxidation of a-hydroxyphosphonates 23 and deprotection of thioacetals. 24 Along this line, we found that potassium permanganate supported on alumina is able to oxidize 2-imidazolines to imidazoles efficiently (Scheme 1).…”

CH Activation: A Complementary Tool in the Total Synthesis of Complex Natural Products

“…Although the phenyl group attached to phosphorus underwent concomitant Birch‐type reduction to form the phosphinodiene 2 (Scheme ), oxidation of 2 with KMnO 4 on alumina resulted in 3 ; to the best of our knowledge, this is the first report of this compound 9. 10 We were able to circumvent the undesired Birch‐type reduction by preparing the naphthyl derivative 1 b . Reductive cleavage of the naphthylethyl fragment in 1 b occurs before the undesired Birch reduction of the phosphine phenyl group.…”