Direct Conversion of Secondary Trimethylsilyl Ethers to Ketones

IMMEDIATE AND HIGH YIELDING SOLVENT-FREE OXIDATION OF SILYL AND PYRANYL ETHERS TO THEIR CORRESPOUNDING CARBONYL COMPOUNDS WITH ZINC DICHROMATE TRIHYDRATE (ZnCr2O7·3H2O)

“…Cinnamyl trimethylsilyl ether was oxidized to cinnamylaldehyde in 88% yield by this method (Table I, entry 9). Saturated primary and secondary trimethylsilyl ethers were converted into the corresponding carbonyl compound in good yields (Table I, entries [13][14][15][16].…”

“…By this procedure, various types of aromatic tetrahydropyranyl ethers with electron-releasing and electron-withdrawing groups (Table III, entries 1-13) were immediately converted to their corresponding carbonyl compounds (85-94%). Primary and secondary aliphatic THP-ethers also were oxidized to the corresponding aldehydes and ketones in 80-85% yields (Table III, entries [13][14][15][16].…”

“…20 Some of the reported procedures for the oxidation of silyl and pyranyl ethers suffer at least from one of the following disadvantages: using expensive reagents, 4,13 high acidity of the media, [14][15][16] long reaction times, 18,19 dangerous procedure for preparation, [21][22][23][24] and difficult procedures. 18 Therefore, efficient and one-pot direct oxidation of silyl and pyranyl ethers under mild and solvent-free conditions can be considered as a useful procedure for further manipulation of the hydroxy functionality in organic synthesis.…”

Allyltriphenylphosphonium Peroxodisulfate (CH2˭CHCH2PPh3)2S2O8: An Efficient and Convenient Reagent for the Oxidation of Alcohols and Silyl and THP‐Ethers Under Nonaqueous Conditions

“…Direct oxidation of trimethylsilyl ethers to the corresponding carbonyl compounds has found considerable attention during recent years. [7 -18] However, some of the reported methods show limitations such as the requirement for aqueous reaction condition, [8,11] use of expensive reagents, [13,17,18] long reaction time, [10,12] low yields of the products, [16] and tedious workup. [11] Therefore, introduction of new methods and inexpensive reagents for such functional group transformation is still in demand.…”

Polyvinylpolypyrrolidone-Bromine Complex, Mild and Efficient Polymeric Reagent for Selective Deprotection and Oxidative Deprotection of Silylethers

“…This transformation can be carried out by either a conventional two-step procedure, deprotection followed by oxidation of the free alcohol, or by a direct oxidative method. Several methods have been described well in the literatures for the oxidative deprotection of silyl ethers including Jone's reagent CrO 3 /H 2 SO 4 /acetone [3][4][5], Jone's reagent with potassium fluoride [6], chromiumoxide/ pyridine [7][8][9] PCC [8,10], PDC [8], ClCrO 2 (OSiMe 3 ) [11], [(Ph 3 SiO) 2 CrO 2 ] [12], activated DMSO [13,14], NBS [15,16] DDQ [17,18], Ph 3 CBF 4 [19,20], NOBF 4 [21], and Ce(NH 4 ) 2 (NO 3 ) 6 /NaBrO 3 [22]. In this study, the PVPP-Br 2 complex is obtained by simple complexation of bromine with crosslinked poly vinylpolypyrrolidone which can release in situ bromine species in reaction media.…”