Baeyer-Villiger Oxidation of β-Aryl Substituted Unsaturated Carbonyl Compounds with Hydrogen Peroxide and Catalytic Selenium Dioxide

Selective Cleavage of Isopropyl Aryl Ethers by Aluminum Trichloride†

“…The resulting solid was dried under reduced pressure to give compound 19 (90%) as a colorless, crystalline solid, mp 98-99°C: IR (KBr disk, cm -1 ) 3378, 1733; 1 H NMR (300 MHz) δ 7.10 (s, 1H), 6.67 (s, 1 H), 6.32 (s, 1H), 3.70 (s, 3H), 2.29 (s, 3H); 13 C NMR (75 MHz) δ 168.9, 146.2, 145.3, 144.7, 119.6, 109.4, 76.3, 56.1, 20.8 i. 3-Hydroxy-2-methoxybenzaldehyde (21). The crude product obtained by treating compound 20 under the reaction conditions defined in the generalized procedure was subjected to flash chromatography (silica, 9:1 hexane/ethyl acetate elution).…”

“…In contrast, when compound 20 was treated with BCl 3 in CH 2 Cl 2 at 0°C a ca. 5:3 mixture of 2,3-dihydroxybenzaldehyde and 3-hydroxy-2-methoxybenzaldehyde (21) was obtained (76% combined yield at 72% conversion). Interestingly, AlCl 3 also has some capacity to effect cleavage of compounds attached to solid supports via a phenolic linkage.…”

Sustainable Syntheses of (−)-Jerantinines A & E and Structural Characterisation of the Jerantinine-Tubulin Complex at the Colchicine Binding Site

“…This proved to be robust and convenient; thus, upon treatment of the Boc-protected 14 with paraformaldehyde in the presence of MgCl 2 and Et 3 N, the C-16-aldehyde 15 was isolated in 98% yield 43 . Exposing 15 to a solution of hydrogen peroxide with a trace amount of SeO 2 44 in tert -butanol gave a complex mixture, and therefore an operationally convenient one-pot procedure was developed; aldehyde 15 was fully oxidised to the quinone, back-reduced with sodium dithionite and the catechol trapped by methylation to give the dimethoxy derivative 16 in 53% yield. Finally, sequential N -Boc deprotection and selective demethylation under Waser’s conditions 20 , furnished (−)-jerantinine A ( 1 ) in 72% yield, and 29% overall yield from (−)-tabersonine ( 4 ).…”

Non-Metal and Enzymatic Catalysts for Hydroperoxide Oxidation of Organic Compounds

“…The reaction extended on the other 2-alkylidenecycloalkanones 55 yielded corresponding enollactones 56 [200] (Scheme 14).…”

“…The Baeyer-Villiger reaction using H 2 O 2 /SeO 2 for various benzaldehydes possessing hydroxy or methoxy substituents mainly in ortho and para position, and/or a furan ring, afforded phenols rapidly in good yield or mixtures of the phenols and carboxylic acids. On the other hand, meta-substituted benzaldehydes or benzaldehydes carrying less effective electron donating groups, electrondeficient heteroaromatic and aliphatic aldehydes were oxidized to the corresponding carboxylic acids [200,202,203].…”